The most common stick grenade manufactured during the First World War, the Model 1917 featured a 5.5 second time-delay fuse that a thrower could activate by pulling a toggle at the base of the handle. The sheet metal covering housed an explosive filling that would kill or wound soldiers by the force of the explosion or by the metal debris it propelled. This model replaced the less reliable Model 1915 concussion grenade, which had depended upon impact with a hard service for its detonation.
Concussion Hand Grenade
CWM 20070067-097