The RGO hand grenade (Ruchnaya Granata Oboronitel'naya) is a defensive Russian fragmentation hand grenade. It consists of a double layered steel pre-fragmented body. It is very similar to the single-layered offensive/defensive 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 and , with the safety radius being . The grenade is still in production in Russia and Ukraine and is in service with a number of countries.