The Geissele Super Duty MOD1 Upper (Complete) features the latest in weapon technology available exclusively from Geissele Automatics. This complete upper chambered in 5.56mm features a nanoweapon-coated HUXWRX Flash Hider-QD muzzle device mounted to an 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 Geissele gas system and Geissele Super Compact Gas Block with bomb-proof installation ensures reliability and optimal performance in extreme conditions.