This kit comes with everything you need to complete your lower receiver so you can install your collapsible stock. Included is your six position mil spec buffer tube, carbine length recoil spring, carbine length recoil buffer, receiver end plate and castle nut. LBE Unlimited is a leading producer of US Made gun parts and accessories. Features: LBE Mil-Spec buffer tube kit 6-position Mil-Spec buffer tube Recoil spring Recoil buffer Receiver end plate Castle nut Made in the USA