The RGO hand grenade (Ruchnaya Granata Oboronitel'naya, ("Hand Grenade Defensive")) is a defensive Soviet fragmentation hand grenade. It consists of a double layered steel pre-fragmented body. It is very similar to the single-layered offensive aluminium-bodied RGN hand grenade. It uses the UDZS dual action fuze, which has both impact and time delay functions. The impact fuze arms after a pyrotechnic delay of 1 to 1.8 seconds. If the impact fuze has not triggered the grenade after 3.2 to 4.2 seconds a second pyrotechnic delay triggers the grenade. The fragments produced by the grenade generate a lethal radius of between 6 metres (20 ft) and 20 metres (66 ft), with the safety radius being 100 metres (330 ft).