This EPC-9 Complete Upper Receiver comes standard with our 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.Includes: EPC-9 Upper Receiver 10.5" ATLAS R-ONE Handguard 11" 9mm CMV Barrel Product comes assembled This complete upper receiver does not include BCG or Charging Handle. These products may be selected as add-ons under the FINISH YOUR BUILD tab. The muzzle device included with this complete upper receiver is NOT pinned nor welded to this barrel.Features: Last round bolt hold open mechanism Accepts most AR15 compatible barrel nuts and handguards Dimple above threads to allow for proper handguard timing Standard AR15 takedown/pivot pin lug pattern Machined from custom forged 7075-T6 aluminum