San Tan Tactical AR-15 Carbine buffer tube kit contains all the necessary parts to mount a stock assembly onto your lower receiver. This six position AR-15 buffer tube is machined from 7075 T6 aluminum to Mil-Spec dimensions. It is finished with Type III, Class II anodized hard coat. The buffer tube has drainage holes to allow water to be evacuated in submerged environments. The machined, high carbon steel castle nut and QD end plate are heat treated for extra strength. They have a nitride finish for durability and corrosion resistance. The kit also contains a standard 3 oz. carbine buffer and carbine action spring made of high-tensile steel. List of parts included in San Tan Tactical Buffer Tube Kit: 6 Position Mil-Spec Carbine Buffer Tube Standard Carbine Recoil Buffer 3oz Castle Nut/Lock Ring QD End Plate