X0206 3 2025-06-13 0 0001555279 908 Devices Inc. MASS 0001836988 Brown Christopher D. C/O 908 DEVICES INC. 645 SUMMER STREET BOSTON MA 02210 true false false false Common Stock 962122.00 D Stock Option (option to buy) 1.75 2027-06-22 Common Stock 114318.00 D Stock Option (option to buy) 3.24 2030-09-21 Common Stock 67604.00 D Stock Option (option to buy) 16.66 2032-03-01 Common Stock 33400.00 D Stock Option (option to buy) 8.83 2033-02-28 Common Stock 45018.00 D Stock Option (option to buy) 7.35 2034-02-28 Common Stock 60064.00 D Restricted Stock Units Common Stock 5027.00 D Restricted Stock Units Common Stock 14836.00 D Restricted Stock Units Common Stock 32974.00 D The shares underlying the option are fully vested and immediately exercisable. Twenty-five percent of the shares underlying the option become vested and exercisable on February 1, 2023, and the remaining 75% of the shares underlying the option become vested and exercisable in substantially equal monthly installments over the 36 months following February 1, 2023, subject to the reporting person's continued service through the applicable vesting date. Twenty-five percent of the shares underlying the option become vested and exercisable on February 1, 2024, and the remaining 75% of the shares underlying the option become vested and exercisable in substantially equal monthly installments over the 36 months following February 1, 2024, subject to the reporting person's continued service through the applicable vesting date. Twenty-five percent of the shares underlying the option become vested and exercisable on February 1, 2025, and the remaining 75% of the shares underlying the option become vested and exercisable in substantially equal monthly installments over the 36 months following February 1, 2025, subject to the reporting person's continued service through the applicable vesting date. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested. This transaction represents the settlement of RSUs in shares of Common Stock on their scheduled vesting date. These RSUs vest in four substantially equal annual installments at the four anniversary dates following February 1, 2022, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date. These RSUs vest in four substantially equal annual installments at the four anniversary dates following February 1, 2023, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date. These RSUs vest in four substantially equal annual installments at the four anniversary dates following February 1, 2024, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date. /s/ Michael S. Turner, as Attorney-in-Fact 2025-06-18