The AR15 Stripped Upper Receiver is one of our most popular products. This stripped upper is precision machined to mil-spec M16/M4 specifications and features M4 feedramps. Match this upper with one of Aero's AR15 lower receivers for a solid and dependable fit. Features- Port door opening have been enlarged to fit .458 SOCOM and other similar rounds, M4 Feedramps, .250 takedown pin holes, laser engraved T-marks, and "XL" portion of Aero Logo on Tang. Works with AR15 lower receivers, compatible with AR15 port door and forward assist. Works with standard AR15/M16 components. Made in the USA. NOTE: Requires dust cover, forward assist, charging handle, barrel, handguard, gas block, muzzle device, gas tube and BCG (Bolt Carrier Group) to complete.