Product Description The Aero Precision M4E1 Assembled Upper Receiver in Anodized Black is a precision-crafted upper receiver built for AR15 enthusiasts who demand both performance and distinctive styling. Featuring a bold angular machined design, this upper stands apart from standard mil-spec receivers while remaining fully compatible with all mil-spec AR15 components. Forged from 7075-T6 Aluminum and precision machined, the M4E1 Assembled Upper ships with the port door and forward assist pre-installed, making it a genuinely drop-in-ready solution for your custom AR15 build. The new Picatinny profile blends seamlessly with Aero Precision Enhanced and ATLAS Series Handguards, and the receiver is engineered to pair perfectly with the M4E1 Lower Receiver, delivering a billet-looking receiver set at a fraction of the billet price. Product Highlights Forged from 7075-T6 Aluminum with precision machining that delivers a billet-style appearance at a competitive price Threaded to accept a standard AR15 barrel nut, ensuring broad compatibility with all mil-spec AR15 components Port door and forward assist come pre-installed for a complete, ready-to-build upper assembly New Picatinny profile integrates seamlessly with Aero Precision Enhanced and ATLAS Series Handguards Includes M4 Feedramps, .250" takedown pin holes, laser engraved T-marks, and threaded forward assist roll pin Specs Brand: Aero Precision Model: M4E1 Assembled Upper Receiver Color / Finish: Anodized Black Material: 7075-T6 Aluminum Compatible Platform: AR15 (Mil-Spec) Barrel Nut Thread: Standard AR15 Feedramps: M4 Takedown Pin Holes: .250" T-Marks: Laser Engraved Includes: Port Door (pre-installed), Forward Assist (pre-installed), Threaded Forward Assist Roll Pin UPC: 815421020977 MPN: APAR700201AC 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.