The Geissele Super Duty Upper features the latest in weapon technology available exclusively from Geissele Automatics. This complete upper chambered in 5.56mm features a Nanoweapon coated Surefire Closed-Tine Warcomp mounted to a Mag Phosphated, CHF, Chrome Lined 1-7 twist barrel. Geissele barrels are precision machined and cold hammer forged utilizing the highest quality materials at their state of the art facility. The carbine length gas tube and Geissele Super Compact Gas Block with bomb-proof installation ensures reliability and optimal performance in extreme conditions.