Collapsible buttstock similar to the current USGI M4 carbine stock provides convenient six-position length-of-pull adjustment to fit different-size shooters, including those wearing body armor. Ready to install on any standard AR-15 rifle or carbine lower receiver; includes 1.17' diameter commercial buffer tube, receiver lock plate, lock nut, toe-mounted steel sling loop, carbine recoil spring and buffer. Convert a fixed-stock, flattop rifle to M4 carbine configuration without permanent alterations to gun. Buttstock made from extremely tough, fiberglass-reinforced, injection-molded nylon that resists impact, heat, moisture, extreme cold, and most cleaning solvents. Stock interior diameter is matched to buffer tube O.D. for a snug fit that eliminates unwanted play and rattles that can give away your position. Steel lock nut has four square notches and pre-cut detents for staking to lock plate. Heavy duty, machined aluminum receiver extension, hardcoat anodized for extra strength, stands up to the punishment of harsh tactical operations. SPECS: Aluminum and fiberglass-reinforced, injection-molded nylon, matte black. 8?” (22.2cm) OAL collapsed; 11?” (29.9cm) OAL fully extended.