Threaded bolt catch pin; An oversized integral trigger guard; A beveled magazine flare that helps you load as quickly and efficiently as possible; Machined top to bottom from 7075-T6 aluminum, a peak-strength corrosion-resistant aluminum alloy; A hard coat anodize finish per MIL-A-8625, the anodizing model for model for most military and aerospace products; Full compatibility with all mil-spec internal parts; Full compatibility with all other aftermarket mil-spec upper receivers; Full compatibility with PMags, Hex mags and other standard capacity magazines; Multi caliber mark; Weight: 10.7 oz