X0609 4 2026-09-15 0001555279 908 Devices Inc. MASS 0001836876 Kenneweg John false C/O 908 DEVICES INC. 44 3RD AVENUE BURLINGTON MA 01803 false true false false SVP, Sales & Product Marketing 1 Common Stock 2026-09-15 4 M 0 1000 0.96 A 58784 D Common Stock 2026-09-15 4 S 0 1000 10 D 57784 D Common Stock 2026-09-16 4 M 0 21399 0.96 A 79183 D Common Stock 2026-09-16 4 S 0 21399 10.11 D 57784 D Common Stock 2026-09-17 4 M 0 5257 0.96 A 63041 D Common Stock 2026-09-17 4 S 0 5257 10.22 D 57784 D Stock Option (right to buy) 0.96 2026-09-15 4 M 0 1000 0 D 2026-12-02 Common Stock 1000 26656 D Stock Option (right to buy) 0.96 2026-09-16 4 M 0 21399 0 D 2026-12-02 Common Stock 21399 5257 D Stock Option (right to buy) 0.96 2026-09-17 4 M 0 5257 0 D 2026-12-02 Common Stock 5257 0 D This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2026. 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. The price reported in Column 4 is a weighted average price. 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. The shares underlying the option are fully vested and immediately exercisable. /s/ Mark S. Levine, Attorney-in-Fact 2026-09-17