This EPC-9 Complete Upper Receiver comes standard with 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. 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 receiver does not include BCG or Charging Handle. The muzzle device included with this complete upper receiver is NOT pinned nor welded to this barrel. Specifications for Aero Precision EPC-9 16in 9mm Threaded Complete Upper Receiver with Flash Hider: Manufacturer: Aero Precision Caliber: 9mm Luger Overall Length: 26 in Barrel Length: 16 in Barrel Profile: Straight Barrel Twist Rate: 1-10 Threads per Inch: 1/2x28 Handguard Type: Free-Float Muzzle Device: A2 Flash Hider Gun Model: Aero Precision EPC-9 Condition: New Fabric/Material: 7075-T6 Aluminum Attachment Type: Picatinny Handguard Length: 15 in Gun Rail: Full Top Rail Gun Type: Rifle Gun Make: Aero Precision Included Accessories: None Barrel Material: 4150 Chrome Moly Vanadium Gas System Type: Blowback Bolt Carrier Group Included: No Charging Handle Included: No Weight: 48.5 oz Magazine Included: No Mount Type: Picatinny Projectile Caliber: .355 Caliber Country of Origin: USA Features of Aero Precision EPC-9 16in 9mm Threaded Complete Upper Receiver with Flash Hider 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 Package Contents: Aero Precision EPC-9 16in 9mm Threaded Complete Upper Receiver with Flash Hider