This custom built AR by PCM Gunsmithing features a Strike Industry’s muzzle break, Balistic Advantage 1/8 twist barrel, Black Rain adjustable gas block, gas tube and other small parts are Aero Precision, UTG Pro hand guard, Spikes Tactical upper and lower, Rise Armament 3lb trigger, Rise Armament nickel boron bolt carrier group, Magpul grip, UTG Pro adjustable stock, Battle Arms Development buffer and spring, Riton quick release one piece scope mount, Firefield 1-6 optic and a lifetime warranty.