Product Description The Aero Precision M4E1 Threaded Complete Upper Receiver is built for shooters who demand performance, reliability, and a refined aesthetic. Finished in a durable Cerakote Flat Dark Earth (FDE) coating, this complete upper pairs the enhanced M4E1 Threaded Upper Receiver with a 15" ATLAS S-ONE M-LOK Handguard and a 16" 5.56 CMV barrel running a mid-length gas system. The S-ONE handguard is engineered with size and weight reduction as top priorities, delivering a slim, lightweight profile without sacrificing the rock-solid stability that Aero Precision is known for. The proprietary ATLAS attachment system provides a durable and dependable mounting platform that seamlessly integrates with the upper receiver. This upper ships fully assembled and is compatible with AR-15 mil-spec components. Please note: BCG and Charging Handle are not included. Product Highlights M4E1 Threaded Upper Receiver: Enhanced forging delivers a billet look, with laser-engraved T-marks, .250 takedown pin holes, M4 feedramps, and forward assist and port door pre-installed. 15" ATLAS S-ONE M-LOK Handguard: Lightweight and slim design featuring front and rear Picatinny rails, indexing grooves at 12 o&';clock, and QD sling sockets at 3, 6, and 9 o&';clock positions. 16" 5.56 CMV Mid-Length Barrel: 4150 CrMoV steel with QPQ finish, 1:7 twist rate, .750 gas block journal, M4 feed ramp extension, and standard A2 flash hider -- HP and MPI tested. Cerakote FDE Finish: The entire assembly is coated in Flat Dark Earth Cerakote for superior corrosion resistance and a consistent, tactical appearance. Comes Fully Assembled: Ready to pair with your lower receiver right out of the box; BCG and Charging Handle sold separately. Specs Brand: Aero Precision Manufacturer Part Number (MPN): APAR700315M7 UPC: 840014601592 Caliber: 5.56x45 NATO / .223 Remington Barrel Length: 16" Barrel Material: 4150 CrMoV (CMV) Barrel Finish: QPQ Twist Rate: 1:7 Gas System: Mid-Length Gas Block Journal: .750" Handguard: 15" ATLAS S-ONE M-LOK Handguard Inside Diameter: 1.3" Handguard Outside Diameter: 1.5" Muzzle Device: Standard A2 Flash Hider Finish: Cerakote Flat Dark Earth (FDE) Firearm Fit: AR-15 Threaded Barrel: Yes Condition: New Includes: BCG and Charging Handle NOT included Country of Manufacture: United States Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&';s manufacturer. ]]>