The LBE AR-15 pistol buffer tube receiver extension comes with no provision to mount a buttstock, allowing your pistol build to remain legally compliant. It features a foam end cap that covers the tail of the buffer tube for use in attaining a more comfortable cheek weld. This kit includes a pistol buffer tube, carbine recoil spring, standard carbine recoil buffer, receiver end plate and castle nut. LBE Unlimited is a leading producer of US-Made gun parts and accessories.