Geissele Automatics Super Duty MOD1, Complete Upper Receiver, 5.56 NATO, 13.9" Pinned (16" OAL) Barrel, M-LOK Free Float Handguard, Geissele Airborne Charging Handle, Nanoweapon Reliability Enhanced Bolt Carrier Group, Fits AR-15, Anodized Finish, Black 08-546B