Machined aluminum stripped lower receivers accept standard AR-15/M16 parts mate with standard upper receiver assemblies and come in custom colors for custom builds. Accepts .250" pivot and takedown pins and are marked as multi caliber. Available in Black Flat Dark Earth and Grey. Mfg: Zero SPECS: 7075 T6 aluminum hardcoat anodized matte black. Uses .250” pivot and takedown pins. Available in Black Flat Dark Earth and Colt grey.