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These shares were sold in multiple transactions at prices ranging from $11.75 to $12.12 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":745559,"source":{"system":"sec-edgar","filing":"0001836988-26-000027","document":"form4-10092026_041001.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1836988/000183698826000027/form4-10092026_041001.xml","form_type":"4"}},{"id":4637934,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":19067,"kind":"person","name":"Griffith Joseph H. IV","position":1,"cik":"0001431531","reported_name":"Griffith Joseph H. 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(SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 198,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"shares","element":"transactionShares","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 198,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 198,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 198,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":4736773,"source":{"system":"sec-edgar","filing":"0001535264-26-000054","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000054/primary_doc.xml","form_type":"4"}},{"id":4626973,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-09-25T20:19:25.000Z","date":"2026-09-24","kind":"sale","planned":false,"acquired":false,"shares":24000,"price":11.3594,"value":272625.6,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"shares","element":"transactionShares","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,962,485 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 560,026 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":4754773,"source":{"system":"sec-edgar","filing":"0001535264-26-000053","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000153526426000053/primary_doc.xml","form_type":"4"}},{"id":4626972,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common 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These shares were sold in multiple transactions at prices ranging from $10.13 to $10.29 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":57784,"source":{"system":"sec-edgar","filing":"0001836876-26-000011","document":"form4-09172026_090941.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1836876/000183687626000011/form4-09172026_090941.xml","form_type":"4"}},{"id":4621756,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-09-17T21:27:45.000Z","date":"2026-09-17","kind":"exercise","planned":true,"acquired":true,"shares":5257,"price":0.96,"value":5046.72,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2026."}],"balance_after":63041,"source":{"system":"sec-edgar","filing":"0001836876-26-000011","document":"form4-09172026_090941.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1836876/000183687626000011/form4-09172026_090941.xml","form_type":"4"}},{"id":4621755,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-09-17T21:27:45.000Z","date":"2026-09-16","kind":"sale","planned":true,"acquired":false,"shares":21399,"price":10.11,"value":216343.89,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.00 to $10.32 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":57784,"source":{"system":"sec-edgar","filing":"0001836876-26-000011","document":"form4-09172026_090941.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1836876/000183687626000011/form4-09172026_090941.xml","form_type":"4"}},{"id":4621754,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-09-17T21:27:45.000Z","date":"2026-09-16","kind":"exercise","planned":true,"acquired":true,"shares":21399,"price":0.96,"value":20543.04,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2026."}],"balance_after":79183,"source":{"system":"sec-edgar","filing":"0001836876-26-000011","document":"form4-09172026_090941.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1836876/000183687626000011/form4-09172026_090941.xml","form_type":"4"}},{"id":4621753,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-09-17T21:27:45.000Z","date":"2026-09-15","kind":"sale","planned":true,"acquired":false,"shares":1000,"price":10,"value":10000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2026."}],"balance_after":57784,"source":{"system":"sec-edgar","filing":"0001836876-26-000011","document":"form4-09172026_090941.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1836876/000183687626000011/form4-09172026_090941.xml","form_type":"4"}},{"id":4621752,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-09-17T21:27:45.000Z","date":"2026-09-15","kind":"exercise","planned":true,"acquired":true,"shares":1000,"price":0.96,"value":960.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2026."}],"balance_after":58784,"source":{"system":"sec-edgar","filing":"0001836876-26-000011","document":"form4-09172026_090941.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1836876/000183687626000011/form4-09172026_090941.xml","form_type":"4"}},{"id":4479,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-09-04T20:15:45.000Z","date":"2026-09-02","kind":"sale","planned":true,"acquired":false,"shares":30000,"price":10.58,"value":317400.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.33 to $10.97 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":775559,"source":{"system":"sec-edgar","filing":"0001836988-26-000025","document":"form4-09042026_080942.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1836988/000183698826000025/form4-09042026_080942.xml","form_type":"4"}},{"id":673732,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":19067,"kind":"person","name":"Griffith Joseph H. IV","position":1,"cik":"0001431531","reported_name":"Griffith Joseph H. 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The reporting person undertakes to provide to Issuer, any security holder of Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote."}],"balance_after":121497,"source":{"system":"sec-edgar","filing":"0001431531-26-000007","document":"form4-08272026_040801.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1431531/000143153126000007/form4-08272026_040801.xml","form_type":"4"}},{"id":677139,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-08-24T20:50:49.000Z","date":"2026-08-21","kind":"sale","planned":false,"acquired":false,"shares":41578,"price":10.6104,"value":441159.2112,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,981,785 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 565,726 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"shares","element":"transactionShares","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,981,785 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 565,726 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,981,785 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 565,726 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 1,981,785 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 565,726 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":4779773,"source":{"system":"sec-edgar","filing":"0001535264-26-000052","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000052/primary_doc.xml","form_type":"4"}},{"id":677138,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-08-24T20:50:49.000Z","date":"2026-08-20","kind":"sale","planned":false,"acquired":false,"shares":8422,"price":10.5246,"value":88638.1812,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."}],"balance_after":4821351,"source":{"system":"sec-edgar","filing":"0001535264-26-000052","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000052/primary_doc.xml","form_type":"4"}},{"id":685193,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-17T21:30:52.000Z","date":"2026-08-17","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":10.35,"value":207000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.08 to $10.45 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":555968,"source":{"system":"sec-edgar","filing":"0001836523-26-000013","document":"form4-08172026_090848.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000013/form4-08172026_090848.xml","form_type":"4"}},{"id":685192,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-17T21:30:52.000Z","date":"2026-08-13","kind":"sale","planned":true,"acquired":false,"shares":7622,"price":10.06,"value":76677.32,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.05 to $10.12 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":575968,"source":{"system":"sec-edgar","filing":"0001836523-26-000013","document":"form4-08172026_090848.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000013/form4-08172026_090848.xml","form_type":"4"}},{"id":688991,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-12T21:05:13.000Z","date":"2026-08-11","kind":"sale","planned":true,"acquired":false,"shares":8358,"price":9.23,"value":77144.34,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.06 to $9.36 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":805559,"source":{"system":"sec-edgar","filing":"0001836988-26-000023","document":"form4-08122026_050808.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000023/form4-08122026_050808.xml","form_type":"4"}},{"id":688990,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-12T21:05:13.000Z","date":"2026-08-10","kind":"sale","planned":true,"acquired":false,"shares":9442,"price":9.03,"value":85261.26,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.00 to $9.08 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":813917,"source":{"system":"sec-edgar","filing":"0001836988-26-000023","document":"form4-08122026_050808.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000023/form4-08122026_050808.xml","form_type":"4"}},{"id":688989,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-12T21:05:10.000Z","date":"2026-08-12","kind":"sale","planned":true,"acquired":false,"shares":2747,"price":10.07,"value":27662.29,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.05 to $10.25 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":583590,"source":{"system":"sec-edgar","filing":"0001836523-26-000011","document":"form4-08122026_050801.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000011/form4-08122026_050801.xml","form_type":"4"}},{"id":688988,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-12T21:05:10.000Z","date":"2026-08-11","kind":"sale","planned":true,"acquired":false,"shares":30170,"price":10.16,"value":306527.2,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.08 to $10.34 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":586337,"source":{"system":"sec-edgar","filing":"0001836523-26-000011","document":"form4-08122026_050801.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000011/form4-08122026_050801.xml","form_type":"4"}},{"id":688987,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-12T21:05:10.000Z","date":"2026-08-11","kind":"sale","planned":true,"acquired":false,"shares":115748,"price":9.83,"value":1137802.84,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.08 to $10.0745 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":616507,"source":{"system":"sec-edgar","filing":"0001836523-26-000011","document":"form4-08122026_050801.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000011/form4-08122026_050801.xml","form_type":"4"}},{"id":688986,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-12T21:05:10.000Z","date":"2026-08-10","kind":"sale","planned":true,"acquired":false,"shares":348,"price":9.06,"value":3152.88,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.05 to $9.08 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":732255,"source":{"system":"sec-edgar","filing":"0001836523-26-000011","document":"form4-08122026_050801.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000011/form4-08122026_050801.xml","form_type":"4"}},{"id":692858,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-07T20:50:30.000Z","date":"2026-08-05","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":8.49,"value":169800.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.35 to $8.595 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":823359,"source":{"system":"sec-edgar","filing":"0001836988-26-000021","document":"form4-08072026_080825.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000021/form4-08072026_080825.xml","form_type":"4"}},{"id":693966,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-08-06T20:26:17.000Z","date":"2026-08-04","kind":"sale","planned":false,"acquired":false,"shares":50000,"price":8.3553,"value":417765.0,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"shares","element":"transactionShares","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 216,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":4829773,"source":{"system":"sec-edgar","filing":"0001535264-26-000041","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000041/primary_doc.xml","form_type":"4"}},{"id":699103,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":27261,"kind":"person","name":"Vann Brandi C","position":1,"cik":"0002081945","reported_name":"Vann Brandi C","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Unit","published_at":"2026-08-03T20:15:06.000Z","date":"2026-08-01","kind":"exercise","planned":false,"acquired":false,"shares":5192,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each Restricted Stock Unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The RSUs become vested in substantially equal annual installments over the 3 years following August 1, 2025, subject to the reporting person's continued service through the applicable vesting date, provided that, if the reporting person terminates their service for any reason, then a prorated number of RSUs will vest. The RSUs have no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The RSUs become vested in substantially equal annual installments over the 3 years following August 1, 2025, subject to the reporting person's continued service through the applicable vesting date, provided that, if the reporting person terminates their service for any reason, then a prorated number of RSUs will vest. The RSUs have no expiration date."}],"balance_after":10385,"derivative":{"underlying":"Common Stock","underlying_shares":5192},"source":{"system":"sec-edgar","filing":"0002081945-26-000005","document":"form4-08032026_040801.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2081945/000208194526000005/form4-08032026_040801.xml","form_type":"4"}},{"id":699102,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":27261,"kind":"person","name":"Vann Brandi C","position":1,"cik":"0002081945","reported_name":"Vann Brandi C","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-03T20:15:06.000Z","date":"2026-08-01","kind":"exercise","planned":false,"acquired":true,"shares":5192,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Each Restricted Stock Unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."}],"balance_after":5192,"source":{"system":"sec-edgar","filing":"0002081945-26-000005","document":"form4-08032026_040801.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2081945/000208194526000005/form4-08032026_040801.xml","form_type":"4"}},{"id":713420,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-07-07T20:45:07.000Z","date":"2026-07-02","kind":"sale","planned":true,"acquired":false,"shares":222,"price":9.07,"value":2013.54,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.062 to $9.07 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":732603,"source":{"system":"sec-edgar","filing":"0001836523-26-000009","document":"form4-07072026_040703.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000009/form4-07072026_040703.xml","form_type":"4"}},{"id":713419,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-07T20:45:06.000Z","date":"2026-07-02","kind":"sale","planned":true,"acquired":false,"shares":2200,"price":9.02,"value":19844.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.00 to $9.07 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":843359,"source":{"system":"sec-edgar","filing":"0001836988-26-000019","document":"form4-07072026_040701.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000019/form4-07072026_040701.xml","form_type":"4"}},{"id":717278,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-02T20:15:15.000Z","date":"2026-06-30","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":8.84,"value":176800.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.61 to $8.95 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":845559,"source":{"system":"sec-edgar","filing":"0001836988-26-000017","document":"form4-07022026_040710.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000017/form4-07022026_040710.xml","form_type":"4"}},{"id":722605,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-06-30T21:10:13.000Z","date":"2026-06-26","kind":"sale","planned":true,"acquired":false,"shares":2798,"price":9.09,"value":25433.82,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.05 to $9.20 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (3) and (4)."}],"balance_after":732825,"source":{"system":"sec-edgar","filing":"0001836523-26-000007","document":"form4-06302026_090609.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000007/form4-06302026_090609.xml","form_type":"4"}},{"id":726211,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-25T21:15:08.000Z","date":"2026-06-23","kind":"sale","planned":true,"acquired":false,"shares":9900,"price":9.04,"value":89496.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.00 to $9.08 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":865559,"source":{"system":"sec-edgar","filing":"0001836988-26-000015","document":"form4-06252026_050603.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000015/form4-06252026_050603.xml","form_type":"4"}},{"id":726196,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-06-25T21:15:05.000Z","date":"2026-06-25","kind":"sale","planned":true,"acquired":false,"shares":16388,"price":9.1,"value":149130.8,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.05 to $9.19 inclusive."}],"balance_after":735623,"source":{"system":"sec-edgar","filing":"0001836523-26-000005","document":"form4-06252026_050601.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000005/form4-06252026_050601.xml","form_type":"4"}},{"id":726195,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-06-25T21:15:05.000Z","date":"2026-06-24","kind":"sale","planned":true,"acquired":false,"shares":40535,"price":9.14,"value":370489.9,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.05 to $9.24 inclusive."}],"balance_after":752011,"source":{"system":"sec-edgar","filing":"0001836523-26-000005","document":"form4-06252026_050601.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183652326000005/form4-06252026_050601.xml","form_type":"4"}},{"id":726194,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":22795,"kind":"person","name":"Knopp Kevin J.","position":1,"cik":"0001836523","reported_name":"Knopp Kevin J.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-06-25T21:15:05.000Z","date":"2026-06-23","kind":"sale","planned":true,"acquired":false,"shares":3422,"price":9.06,"value":31003.32,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.05 to $9.08 inclusive. 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The RSUs have no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The RSUs become vested in substantially equal annual installments over the 3 years following June 25, 2024, subject to the reporting person's continued service through the applicable vesting date, provided that, if the reporting person terminates their service for any reason, then a prorated number of RSUs will vest. 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(SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 266,802 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  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The RSUs have no expiration date."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":14083},"source":{"system":"sec-edgar","filing":"0001252546-26-000003","document":"form4-06122026_080654.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1252546/000125254626000003/form4-06122026_080654.xml","form_type":"4"}},{"id":739432,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":38631,"kind":"person","name":"HRUSOVSKY E KEVIN","position":1,"cik":"0001252546","reported_name":"HRUSOVSKY E KEVIN","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-12T16:49:58.000Z","date":"2026-06-10","kind":"exercise","planned":false,"acquired":true,"shares":14083,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Each Restricted Stock Unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."}],"balance_after":165390,"source":{"system":"sec-edgar","filing":"0001252546-26-000003","document":"form4-06122026_080654.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1252546/000125254626000003/form4-06122026_080654.xml","form_type":"4"}},{"id":747522,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-05T22:49:53.000Z","date":"2026-06-04","kind":"sale","planned":true,"acquired":false,"shares":100,"price":9,"value":900.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."}],"balance_after":875459,"source":{"system":"sec-edgar","filing":"0001836988-26-000013","document":"form4-06052026_100649.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000013/form4-06052026_100649.xml","form_type":"4"}},{"id":749266,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-06-04T20:43:47.000Z","date":"2026-06-04","kind":"sale","planned":false,"acquired":false,"shares":39782,"price":8.9703,"value":356856.4746,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,025,616 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 578,813 Shares held by CAY, 267,602 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,025,616 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 578,813 Shares held by CAY, 267,602 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,025,616 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 578,813 Shares held by CAY, 267,602 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":4887491,"source":{"system":"sec-edgar","filing":"0001535264-26-000034","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000034/primary_doc.xml","form_type":"4"}},{"id":749265,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-06-04T20:43:47.000Z","date":"2026-06-02","kind":"sale","planned":false,"acquired":false,"shares":2500,"price":8.95,"value":22375.0,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."}],"balance_after":4927273,"source":{"system":"sec-edgar","filing":"0001535264-26-000034","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000034/primary_doc.xml","form_type":"4"}},{"id":749247,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-04T20:15:06.000Z","date":"2026-06-03","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":8.73,"value":174600.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.61 to $8.86 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":875559,"source":{"system":"sec-edgar","filing":"0001836988-26-000011","document":"form4-06042026_040601.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000011/form4-06042026_040601.xml","form_type":"4"}},{"id":758460,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-29T20:48:52.000Z","date":"2026-05-28","kind":"sale","planned":false,"acquired":false,"shares":170442,"price":8.6594,"value":1475925.4548,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price"},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,054,000 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 588,327 Shares held by CAY, 271,986 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,054,000 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 588,327 Shares held by CAY, 271,986 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,054,000 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 588,327 Shares held by CAY, 271,986 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."}],"balance_after":4929773,"source":{"system":"sec-edgar","filing":"0001535264-26-000033","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000033/primary_doc.xml","form_type":"4"}},{"id":758459,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-29T20:48:52.000Z","date":"2026-05-27","kind":"sale","planned":false,"acquired":false,"shares":15000,"price":8.2527,"value":123790.5,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price"}],"balance_after":5100215,"source":{"system":"sec-edgar","filing":"0001535264-26-000033","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000033/primary_doc.xml","form_type":"4"}},{"id":758458,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-29T20:48:52.000Z","date":"2026-05-27","kind":"sale","planned":false,"acquired":false,"shares":1500,"price":8.25,"value":12375.0,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price"}],"balance_after":5115215,"source":{"system":"sec-edgar","filing":"0001535264-26-000033","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000033/primary_doc.xml","form_type":"4"}},{"id":758635,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":19067,"kind":"person","name":"Griffith Joseph H. 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(SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,179,495 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 630,388 Shares held by CAY, 291,372 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,179,495 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 630,388 Shares held by CAY, 291,372 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,179,495 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 630,388 Shares held by CAY, 291,372 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":5116715,"source":{"system":"sec-edgar","filing":"0001535264-26-000030","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000030/primary_doc.xml","form_type":"4"}},{"id":784388,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-05-11T20:05:07.000Z","date":"2026-05-08","kind":"sale","planned":false,"acquired":false,"shares":18255,"price":8.11,"value":148048.05,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.99 to $8.20 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":57784,"source":{"system":"sec-edgar","filing":"0001836876-26-000009","document":"form4-05112026_040501.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183687626000009/form4-05112026_040501.xml","form_type":"4"}},{"id":786308,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-08T20:40:33.000Z","date":"2026-05-08","kind":"sale","planned":false,"acquired":false,"shares":3025,"price":8.2,"value":24805.0,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,182,852 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 631,513 Shares held by CAY, 291,890 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,182,852 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 631,513 Shares held by CAY, 291,890 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds).  As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,182,852 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 631,513 Shares held by CAY, 291,890 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":5121715,"source":{"system":"sec-edgar","filing":"0001535264-26-000029","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000029/primary_doc.xml","form_type":"4"}},{"id":786307,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-08T20:40:33.000Z","date":"2026-05-07","kind":"sale","planned":false,"acquired":false,"shares":12819,"price":8.2042,"value":105169.6398,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."}],"balance_after":5124740,"source":{"system":"sec-edgar","filing":"0001535264-26-000029","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000029/primary_doc.xml","form_type":"4"}},{"id":786306,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-08T20:40:33.000Z","date":"2026-05-06","kind":"sale","planned":false,"acquired":false,"shares":57365,"price":8.0564,"value":462155.386,"ownership":{"direct":false,"nature":"By Limited Partnership"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"This is a weighted average price."}],"balance_after":5137559,"source":{"system":"sec-edgar","filing":"0001535264-26-000029","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000029/primary_doc.xml","form_type":"4"}},{"id":786305,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":20260,"kind":"organization","name":"AWM Investment Company, Inc.","position":1,"cik":"0001535264","reported_name":"AWM Investment Company, Inc.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"908 DEVICES, INC.","published_at":"2026-05-08T20:40:33.000Z","date":"2026-05-06","kind":"sale","planned":false,"acquired":false,"shares":5000,"price":8,"value":40000.0,"ownership":{"direct":false,"nature":"By Limited Partnership"},"balance_after":5194924,"source":{"system":"sec-edgar","filing":"0001535264-26-000029","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1535264/000153526426000029/primary_doc.xml","form_type":"4"}},{"id":788262,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":10078,"kind":"person","name":"Brown Christopher D.","position":1,"cik":"0001836988","reported_name":"Brown Christopher D.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-05-07T20:30:19.000Z","date":"2026-05-06","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":7.23,"value":144600.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.49 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":925559,"source":{"system":"sec-edgar","filing":"0001836988-26-000007","document":"form4-05072026_040501.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183698826000007/form4-05072026_040501.xml","form_type":"4"}},{"id":793543,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Performance Stock Units","published_at":"2026-05-04T20:30:16.000Z","date":"2026-05-01","kind":"exercise","planned":false,"acquired":false,"shares":26042,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each performance stock unit (\"PSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The PSUs vested, in accordance with their terms, on May 1, 2026. The PSUs had no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The PSUs vested, in accordance with their terms, on May 1, 2026. 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The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by a \"sell to cover\" transaction and does not represent a discretionary transaction by the Reporting Person."}],"balance_after":76039,"source":{"system":"sec-edgar","filing":"0001836876-26-000007","document":"form4-05042026_040510.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183687626000007/form4-05042026_040510.xml","form_type":"4"}},{"id":793541,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Common Stock","published_at":"2026-05-04T20:30:16.000Z","date":"2026-05-01","kind":"exercise","planned":false,"acquired":true,"shares":26042,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Each performance stock unit (\"PSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."}],"balance_after":83826,"source":{"system":"sec-edgar","filing":"0001836876-26-000007","document":"form4-05042026_040510.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183687626000007/form4-05042026_040510.xml","form_type":"4"}},{"id":797844,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":48284,"kind":"person","name":"Kenneweg John","position":1,"cik":"0001836876","reported_name":"Kenneweg John","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Sales & Product Marketing"}}],"security":"Performance Stock Units","published_at":"2026-04-29T20:05:13.000Z","date":"2026-04-28","kind":"grant","planned":false,"acquired":true,"shares":26042,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each performance stock unit (\"PSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The Issuer's compensation committee of the Board of Directors certified the achievement of the applicable performance metrics and goals on April 28, 2026. The PSUs will vest, in accordance with their terms, on May 1, 2026. The PSUs have no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The Issuer's compensation committee of the Board of Directors certified the achievement of the applicable performance metrics and goals on April 28, 2026. The PSUs will vest, in accordance with their terms, on May 1, 2026. The PSUs have no expiration date."}],"balance_after":26042,"derivative":{"underlying":"Common Stock","underlying_shares":26042},"source":{"system":"sec-edgar","filing":"0001836876-26-000005","document":"form4-04292026_040403.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000183687626000005/form4-04292026_040403.xml","form_type":"4"}},{"id":802540,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":51603,"kind":"person","name":"Otitoju Kolawole A.","position":1,"cik":"0002127645","reported_name":"Otitoju Kolawole A.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Bus. & Strategy Officer"}}],"security":"Restricted Stock Units","published_at":"2026-04-22T12:08:48.000Z","date":"2026-04-21","kind":"grant","planned":false,"acquired":true,"shares":110193,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"These RSUs vest in three substantially equal annual installments at the three anniversary dates following May 1, 2026, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"These RSUs vest in three substantially equal annual installments at the three anniversary dates following May 1, 2026, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date."}],"balance_after":110193,"derivative":{"underlying":"Common Stock","underlying_shares":110193},"source":{"system":"sec-edgar","filing":"0002127645-26-000004","document":"form4-04222026_120444.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000212764526000004/form4-04222026_120444.xml","form_type":"4"}},{"id":802539,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":51603,"kind":"person","name":"Otitoju Kolawole A.","position":1,"cik":"0002127645","reported_name":"Otitoju Kolawole A.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Bus. & Strategy Officer"}}],"security":"Stock Option (right to buy)","published_at":"2026-04-22T12:08:48.000Z","date":"2026-04-21","kind":"grant","planned":false,"acquired":true,"shares":146789,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"One-third of the shares underlying the option become vested and exercisable on May 1, 2027, and the remaining two-thirds of the shares underlying the option become vested and exercisable in substantially equal monthly installments over the 24 months following May 1, 2027, subject to the reporting person's continued service through the applicable vesting date."}],"balance_after":146789,"derivative":{"exercise_price":7.26,"expiration_date":"2036-04-20","underlying":"Common Stock","underlying_shares":146789},"source":{"system":"sec-edgar","filing":"0002127645-26-000004","document":"form4-04222026_120444.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1555279/000212764526000004/form4-04222026_120444.xml","form_type":"4"}},{"id":808625,"issuer":{"id":5564,"kind":"organization","name":"908 Devices Inc.","symbol":"MASS"},"owners":[{"id":52509,"kind":"person","name":"McCallion Kevin J.","position":1,"cik":"0002115341","reported_name":"McCallion Kevin J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"SVP, Products and Production"}}],"security":"Stock Option (right to buy)","published_at":"2026-04-14T20:00:05.000Z","date":"2026-04-10","kind":"exercise","planned":true,"acquired":false,"shares":2693,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 9, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The shares underlying the option are fully vested and immediately exercisable."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Due to a scrivener's error on the Form 3, the number of stock options beneficially owned by the Reporting Person pursuant to this grant was understated by 7. 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These shares were sold in multiple transactions at prices ranging from $7.00 to $7.03 inclusive. 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