This is a 6 position adjustable stock which allows you to fit the rifle to your needs. The buttstock had a commercial stock body manufactured from the highest grade components. Our extension tube is second to none and just like the stock body, meets all military requirements. This is the best fit between the stock body and the tube, minimizing any rattle that might occur with cheaper stocks. You will find this tube is crafted from the same aluminum that most AR receivers are made from, ensuring a much stronger part.This stock assembly fits the AR-15, M16 and M4 rifle platforms. This Item comes with a Commercial Stock Body Assembly,Commercial AR Carbine Receiver Extension Tube, AR Carbine Buffer Spring, Buffer, AR Carbine Castle Nut, & AR Carbine Locking Plate.