Our M4A1 Clone Complete Lower Receiver features custom engraving on our AR15 Gen 2 Lower Receiver and is the perfect complete lower for your M4A1 clone build. - Includes: - M4A1 Clone Lower Receiver - Standard Collapsible Stock - Standard A2 Grip - Lower parts kit - Receiver extension - Carbine buffer kit - These parts are installed - M4A1 Lower Receiver Features: - Custom Aero Precision logo - Markings include: Property of U.S.A. MOD M4 CARBINE CAL. 5.56MM - Serial number designation - Safe/Semi/Auto safety selector markings - Gen 2 Lower Receiver Features: - Upper Tension Screw- Allows users to fine tune the fit of the upper and lower receiver through the use of a nylon tipped tensioning set screw inserted in the grip tang of the lower receiver. This provides a tight fit with any standard AR15 upper receiver. - Increased Magwell Flare- Allows for easier insertion of magazines and provides a sleeker look.