BILLET LOWER RECEIVER (AS SEEN ON THE MODEL-57)YHM is proud to offer our first Billet Lower Receiver. We originally designed a Billet lower that mimicked a standard (forged) lower receiver, but after seeing the prototype production we decided to go with a receiver that was more stylized, something that didn't look like every other AR-15 on the planet. It was this mindset that helped us arrive at the MODEL-57, and in turn this lower receiver...These lowers were designed, and are machined 100% in house from 7075-T6 aluminum (Billet)Features over sized magazine well chamfers for easier magazine changesAccepts All Generations of PMAG'sAccepts Mil-Spec Upper receiversBuilt in oversized machined trigger guardFits all standard parts (except for a trigger guard)Hardcoat Anodized matte black to Military Specifications or betterThis lower still fits, and functions with your standard upper receiversTension Screw built into lower for unmatched mate with any Mil-Spec upperWeight: 11.2 Oz.