This is a Smith Enterprises AR15 auto sear. It is currently housed in a Bushmaster XM15-E2S 5.56mm rifle. This rifle has a 10.5" barrel. It comes with a non-removeable carry handle, a collapsible stock, and a flashhider. This select fire auto sear may be dropped into any AR-15 configuration rifles. The sear itself is the registered Class III item. The rifle is just the host gun. All NFA rules apply.