The LBE AR-15 buffer tube kit gives you the receiver-extension hardware needed to mount a collapsible carbine stock on a mil-spec AR-15 lower. Brown finish. Stock is not included. Fit: AR-15 mil-spec lowers and mil-spec diameter carbine stocks. Not compatible with commercial-spec tubes or stocks. Includes: 6-position mil-spec diameter buffer tube - hard-coat anodized aluminum, rolled threads Standard carbine recoil buffer Carbine-length recoil spring Steel receiver end plate Steel castle nut, cut for stake-engagement LBE Unlimited is a US manufacturer of mil-spec AR parts. Best practice: torque the castle nut to spec and stake it to keep it from backing out under repeated cycling. Verify your lower is mil-spec before install.