This kit comes with everything you need to complete your lower receiver so you can install your collapsible stock. Included is your classic M4 style buttstock, 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: AR-15 Mil-Spec buttstock kit M4 style buttstock- 6 position Mil-Spec tube Recoil spring and buffer Receiver end plate Castle nut Made in the USA