Improved ergonomics, vital storage capacity and Battle Ready toughness define Troy’s new Battle Ax M4 butt stock. Advanced reinforced polymer ensures strength and durability. A comfortable cheek weld helps operators settle in quickly for rapid target acquisition. The stock collapses compactly and securely. A solid metal butt plate opens to reveal storage capacity unmatched by any other stock on the market. For Mil-Spec receiver extensions tube only. Made in the U.S.A. *Lifetime limited warranty Features: - Kit includes mil-spec receiver extension, end plate, buffer, buffer spring, castle nut and stock. - Features QD swivel sockets at 9-6-3 o’clock. - Includes heavy duty QD push button swivel. - Patent Pending. - Flat Dark Earth