X0508 4 2025-06-12 false 0001555279 908 Devices Inc. MASS 0002027457 Leonhart Michele M. C/O 908 DEVICES INC. 645 SUMMER STREET BOSTON MA 02210 true false false false false Restricted Stock Units 2025-06-12 4 A false 14083.00 0.00 A Common Stock 14083.00 14083.00 D Stock Option (option to buy) 7.19 2025-06-12 4 A false 6516.00 0.00 A 2035-06-11 Common Stock 6516.00 6516.00 D Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested. The RSUs become fully vested on June 12, 2026 or the day prior to the 2026 Annual Meeting of the Stockholders of 908 Devices Inc., whichever occurs first, 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. The shares underlying the option become vested and exercisable in substantially equal monthly installments over the 12 months following June 12, 2025, subject to the reporting person's continued service through the applicable vesting date. /s/ Michael S. Turner, as Attorney-in-Fact 2025-06-13