Commercial spec AR-15 lower receiver, made to the highest standards. Machined from a 7075 aluminum forging and finished with MIL spec hard coat anodizing. Marked "MULTI" for caliber, model is SFI-15. This is a limited run...get 'em while you can! Our last small run of 100 of these sold out almost immediately. (Note that this part is considered a firearm and by law must be shipped to a federally licensed dealer (FFL) only). Yeah, we know...everybody and their brother has an AR-15 lower receiver on the market, but this is your chance to get one with SERBU FIREARMS on the side!