In March, 1918, The US released the first version of the MK3 hand grenade. This grenade is a cylindrical concussion(HE) grenade designed to deal damage to enemies in close combat, while reducing damage to allies due to less fragmentation. (The shockwaves produced were what killed/stunned enemies, not the shrapnel.) The grenade is also used for concussion effects in enclosed areas or for demolition tasks. The shock waves that these grenades produced were more powerful than fragmentation grenades, and therefore proved very effective when used in buildings, and fortified areas. It is commonly known as the “concussion” or “demo” (from demolition) grenade.