A hand-throwable grenade including a detonator initiating mechanism, a detonator and a locking key. The detonator initiating mechanism is activatable by an operator before the grenade is thrown. The detonator is associated with the detonator initiating mechanism. The locking key interacts with the detonator initiating mechanism to preclude an arming of the detonator until the locking key is removed from the detonator initiating mechanism. The locking key has at least one notch therein.