This complete upper includes our new ATLAS R-ONE Handguard! The R-ONE handguards are designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. Our proprietary ATLAS attachment system is a durable and dependable mounting platform, maintaining a slim profile while still providing the strength and stability customers have grown to love from Aero Precision handguards.Features: New enhanced forging that gives the upper receiver a billet look New picatinny profile that blends seamlessly with our Enhanced Series Handguards M4 Feedramps .250 takedown pin holes Laser engraved T-marks Includes port door and forward assist installedSpecifications: Manufacturer: Aero Precision Cartridge: 5.56x45mm NATO Barrel Profile: Government Barrel Twist Rate: 1-7 Threads per Inch: 1/2x28 Handguard Type: A2 Muzzle Device: A2 Flash Hider Gun Model: AR-15 Handguard Length: 15 in Gun Type: Rifle Gun Make: AR Platform Barrel Material: 4150 CMV Steel Bolt Carrier Group Included: No Charging Handle Included: No