Features: Platform: FM-9b Caliber: 9mm Op. System: Straight Blowback Barrel Length: 16" Barrel Contour: Lightweight Barrel Material: 41v50 Barrel Finish: Black Nitride Barrel Twist: 1:10 Muzzle Device: Micro Blast Diffuser Muzzle Thread: 1/2 X 36 Trigger Type: USGI Mil-spec Weight: 6.0 Lbs. Length: 31.5" Hand Guard: 15" Mlok Free Float Charging Handle: Mil-spec Rear Charge Safety Selector: FM Products Ambi. Receiver Material: Billet Aircraft Aluminum Receiver Finish: Type III Hard Black Anno. Receiver Extension: Mil-spec Stock / Brace: Mil-spec M4 Stock Pistol Grip: A2 Mil-spec Trigger Guard: Integrated