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. M4E1 Threaded Assembled Upper Receiver ATLAS R-ONE Handguard of choice 18" .223 Wylde Rifle Length Stainless Steel Barrel Low Profile Gas Block and Rifle Length Gas Tube Product comes assembled