This is a U.S. Mil-Spec. Flash Bang Diversionary Device Training System. This system is manufactured by A.L.S. Technologies, the single largest supplier of diversionary devices for U.S. Military and law enforcement contracts. This system consists of one steel body and five fuzes. You simply screw a fuze into the body, pull the pin and throw it. In 2 to 3 seconds it will detonate with a report of 130db and a 750,000 candela flash. The bottom of the body has baffled holes which releases the report and the flash. You can then go pick up the body, unscrew the spent fuze and screw in a new fuze. The body can be used over 1000 times and additional fuzes can be purchased. This training system is completely legal to own and is unregulated by the ATF at this time.