These 16" M-4 style Upper Halves feature an extra heavy 4140 Chrome-Moly barrel. Includes a forged and hard coat anodized A3 upper receiver with flat top rail, ejection port cover, forward assist, a rear sight, M4 feed ramps and a 1 in 9 twist. Pre-ban. Includes a flashider and a bayonet lug. No FFL required. Easy installation--remove 2 pins, insert upper and replace pins.