Aero Precision M4E1 Enhanced Upper Receiver is a one-piece design combining the handguard mounting platform with the upper itself. Through superior engineering, Aero Precision condensed the parts needed to mount a free-floated handguard to a mere 8 screws. Since the handguard mounting surface and upper are of the same forging, not only is it a stronger system, but they were able to make additional lightening cuts to save weight and allow for more efficient cooling. Ease of installation - Simply insert your barrel assembly into the M4E1 upper, tighten it using the provided barrel nut and wrench, slide your rail on and tighten the rail screws. Within minutes you have a modular, free-floated rail.Features:M4 Feedramps.250 takedown pin holesComes assembled, with dust cover and forward assist installedM4E1 Specific Details:Handguard mounting platform is forged into the receiverCompatible with Aero Precision Enhanced and Quantum Series handguards but also fits most BAR-system handguardsBa...