Compatible with Mil-Spec AR-15 stocks, this kit contains all the necessary parts to mount a stock assembly onto your lower receiver.Six position AR-15 buffer tube is machined from 7075 T6 aluminum to Mil-Spec dimensions with a Type III, Class II hard coat anodized finish. Buffer tube has through drainage holes to allow water to be evacuated in submerged environments.Machined, high carbon steel Castle Nut and Quick Detach End Plate are heat treated for extra strength and given a nitride finish for durability and corrosion resistance. Kit contains a standard 3 oz. carbine buffer and a carbine action spring made of high-tensile steel.Upgraded QD - Quick Detach End Plate included as an easy way to attach your QD Sling to your rifle.Complete your lower build by adding your favorite CMC Trigger and CMC Lower Parts Kit.6 Position Mil-Spec Carbine Buffer TubeStandard Carbine Recoil Buffer 3ozHigh Quality Recoil SpringCastle Nut/Lock RingQD Receiver End PlateNitride Coated Hardware7075 T6 Grade AluminumOTB Drainage HolesASTM Certified US MaterialMade in the USA