Mil-spec forged 7075-t6 completely assembled upper rec.Type iii hard coat anodized for maximum durability.M4 barrel extensions.10.50" 4150 cmv steel and bolt is 9310 tool steel.Both are nitride finish with excellent lubricity and corrosion resistance properties.Full auto profile.Includes charging handle and complete lower parts kit to build your ar-pistol.Ar pistol buffer tube, 3.0 oz buffer, carbine buffer spring, castle nut, and end plate.Lpk comes with fire control group and a2 grip.Receiver Finish: Black Hard Coat AnodizedType: CompleteCaliber: 5.56x45mm NATOSights: None, Optic ReadyBarrel Length: 10.50"Barrel Material: 4150 Chrome Moly Vanadium SteelTwist: 1:8"Barrel Finish: Black NitrideHandguards: 10" M-LOKHandguard Finish: Black Hard Coat AnodizedBarrel Length Range: 10" to 10.99"