The M228 is a pyrotechnic delay igniting fuze used in conjunction with the M69 Grenade body, as a trainer for the M67 Fragmentation Hand Grenade. The fuze is equipped with a steel safety pin and pull ring, and a safety clip. The safety pin and the safety clip are removed to arm the grenade while holding the lever tight to the grenade body. The M228 emits a small puff of smoke when activated.
When the lever is released, the spring-loaded striker rotates and initiates the primer. The primer ignites a delay element, which initiates the igniter. The igniter produces an audible signal and a white smoke charge.