The Geissele Super Duty Upper (Complete) features the latest in weapon technology available exclusively from Geissele Automatics. This 14.5" complete upper chambered in 5.56mm features a Geissele HuxWrx Flash Hider mounted to an 14.5" Manganese Phosphate coated, CHF, Chrome Lined 1-7 twist barrel. Our barrels are precision machined and cold hammer forged utilizing the highest quality materials at our state of the art facility in North Wales, PA. The mid length length gas system and Geissele Super Compact Gas Block with bomb-proof installation ensures reliability and optimal performance in extreme conditions.LENGTH: 14.5"CALIBER: 5.56MMCOLOR: BlackRECEIVER: Super Duty Upper w/ cam Pin cut-outBOLT CARRIER GROUP: Nanoweapon Reliability Enhanced BCGBOLT: Geissele Stressproof Bolt with Asymmetric Cam PinRAIL: 13.5" SMR MK16BARREL: 14.5" Geissele Barrel, CHF, Chrome Lined, 1-7 Twist - Geissele Profile (Pin & Weld)GAS SYSTEM: Mid LengthGAS BLOCK: Super Compact Gas BlockGAS PORT SIZE: .076"CHARGING HANDLE: Airborne Charging Handle