The RGO hand grenade, which stands for Hand Grenade Defensive, is a defensive fragmentation hand grenade originally developed by the Soviet Union. It features a double-layered pre-fragmented steel body and is similar to the offensive RGN hand grenade, which has a single-layered aluminum body. The grenade utilizes the UDZS dual-action fuze that combines both impact and time delay functions. After a pyrotechnic delay of 1 to 1.8 seconds, the impact fuze arms, and if it does not detonate within 3.2 to 4.2 seconds, a second pyrotechnic delay triggers the grenade.

The fragments produced by the grenade create a lethal radius ranging from 6 meters (20 ft) to 20 meters (66 ft), with a safety radius of 100 meters (330 ft). Unlike the two-part hemispherical RGN, the RGO consists of four quadrants, one of which has a diamond-shaped cross-hatching on the outer shell. This feature is designed to help operators distinguish it from the smooth-shelled RGN in low-light or dark conditions through tactile feedback