Aero Precision APAR700705M8: This complete upper includes Aero Precision's 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. Aero Precision's 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. This complete upper does not include BCG or Charging Handle.Includes: M4E1 Threaded Assembled Upper Receiver 15" ATLAS R-ONE Handguard 18" 5.56 Rifle Length CMV Barrel Low Profile Gas Block and Rifle Length Gas Tube Product comes assembled