This Complete Upper includes our Gen 2 Enhanced Handguard! Key features include the addition of quick disconnect sling sockets, enhanced milling design for grip and visual appeal and a new profile for the picatinny top rail. This complete upper does not include BCG or Charging Handle. These products may be selected as add-ons. Specifications for Aero Precision M4E1 16in .223 Wylde Complete Upper Receiver with Flash Hider: Manufacturer: Aero Precision Cartridge: .223 Wylde Overall Length: 26 in Barrel Length: 16 in Barrel Profile: SPR Gas System Length: Mid Length Barrel Twist Rate: 1-8 Threads per Inch: 1/2x28 Muzzle Device: A2 Flash Hider Gun Model: AR-15 Condition: New Fabric/Material: 7075-T6 Aluminum Gas Block Journal Size-Diameter: .750 in Handguard Length: 15 in Gun Rail: Picatinny Gun Make: AR Platform Included Accessories: None Barrel Material: 416R Stainless Steel Gas Block Journal Size-Length: .750 in Weight: 48.5 oz Magazine Included: No Mount Type: M-LOK Country of Origin: USA Features of Aero Precision M4E1 16in .223 Wylde Complete Upper Receiver with Flash Hider M4E1 Upper Receiver Features: Forged from 7075 T6 aluminum Precision machined to M4E1 specs M4 feedramps Laser engraved T-marks Comes assembled, with port door and forward assist installed Accepts standard AR15/M16 components Handguard mounting platform is forged into the receiver Works with Aero Precision handguards but also fits most BAR-system handguards Barrel nut and wrench are included Gen 2 Enhanced Handguard Features: 1pc free float design Built in anti-rotation tabs Scalloped rails Continuous top rail 1.78in inside diameter fits most muzzle devices and 1.5in suppressors Compatible with low profile gas blocks Gen 2 Feature - Quick disconnect sling socket at the 3, 6 and 9 o'clock positions Gen 2 Feature - Additional milling along flats to aid with gripping and add visual appeal Gen 2 Feature - New profile for the continuous picatinny top rail .223 Wylde Stainless Steel QPQ Barrel Features: .223 Wylde Barrel, 1/8 Twist QPQ Corrosion Resistant Finish .750 gas block journal M4 Feed Ramp Extension HP and MPI tested Standard A2 flash hider Package Contents: Aero Precision M4E1 16in .223 Wylde Complete Upper Receiver with Flash Hider M4E1 Enhanced Upper Receiver 15in Enhanced M-LOK Handguard of choice .223 Wylde Stainless Steel QPQ Barrel Pinned Low Profile Gas Block and Gas Tube A2 Flash Hider Product comes assembled