Complete 16" Anonymous Arms 5.56 Forged Upper Receiver with a mid length gas system and a 416R Stainless Steel Socom Mid Barrel with a 1/8 Twist. Fortis REV-12 Free Float Rail. All Mil-spec, US Made parts including a Nitride Bolt Carrier Group for longer life and durability. Solid steel low profile gas block. HPT (High Pressure Tested) and MPI (Magnetic Particle Inspected) Bolt and Barrel. Charging handle included.