Aluminum alloy build provides great durability. Matte black finish to give airsoft a more realistic appearance. Light weight design doesn't impede performance. Quick an easy installation with compatible AEG rifles. Available to mount more custom accessories to your airsoft gun. In the Box 1X Lower Receiver Specifications: Manufacturer Krytac Build Aluminum Alloy Compatible M4 / M16 series California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov