The ASM (Anti-Structure Munition) is an American hand-launched high-explosive fragmentation grenade developed for the U.S. Special Operations Command (USSOCOM). The loaded grenade weighs 420 g, has a diameter of 63.5 mm, and a body length of 112.3 mm without the fuse and 134.6 mm with the fuse. It is loaded with PBXN-109 explosive, with a total weight of approximately 390 grams. The use of PBXN-109, which is an explosive based on hexogen, a plasticizer, and aluminum powder, has led to it being mistakenly referred to as a thermobaric grenade.