Stripped lower made from ultra-light proprietary magnesium alloy by Fostech Arms. Fostech's AR15 lower receiver is 35% lighter than standard lowers on the market today while also being one of the strongest and most rugged lowers in the market. Not satisfied with being just the lightest lower on the market Fostech has reinforced key areas of the receiver including the front pivot pin location and the trigger and hammer pin area making these tougher than nails. Longer trigger pin set included. Premium Grade, Ulta Light Weight AR-15 Lower.  Fighter Lite Serie's. Limited Lifetime Warranty.