The Jack Gen-2 by Sharps Bros is an exceptionally unique lower for your next build. The Jack - Gen2 features now include a threaded bolt catch pin, reduced weight and improved styling. The styling does nothing to interfere with most standard capacity magazines and the beveled magazine flare helps for quick and efficient loading. FeaturesUnique Skull DesignMachined top to bottom from 7075-T6 aluminum, a peak-strength corrosion-resistant aluminum alloyA hard coat anodize finish per MIL-A-8625, the anodizing model for model for most military and aerospace productsFull compatibility with all mil-spec internal partsFull compatibility with all other aftermarket mil-spec upper receivers