grenade pin

A part of hand grenade.

The classic hand grenade design has a safety handle or lever (known in the US forces as a spoon) and a removable safety pin that prevents the handle from being released: the safety lever is spring-loaded, and once the safety pin is removed, the lever will release and ignite the detonator, then fall off. Thus, to use a grenade, the lever is grasped (to prevent release), then the pin is removed, and then the grenade is thrown, which releases the lever and ignites the detonator, triggering an explosion. Some grenade types also have a safety clip to prevent the handle from coming off in transit.