The K-40 is a 4oz grenade filled with composition 4 high explosives. It is usually thrown in clusters as the picture depicts; this is referred to a "grape bunch" in which they are chained together and you pull one pin which is chained to the two pins that are on the grenade. Usually thrown in groups of 2, 3 or 4. The lethal radius is approximately 12 meters and has preformed shrapnel molded to the inside. Based upon the V-40 mini grenade.