Designed with quality and durability in mind, the Matrix Arms M15 stripped lower receivers are CNC machined from an American made mil-spec 7075 T-6 aluminum forging. They utilize a standard .250 take down/pivot pin hole and standard .156 fire control pins. Like our other products they are finished with a premium black anodize finish. Matched flawlessly to our 5.56 lower is our M15 Matrix stripped upper receiver. It features a Mil-Std 1919 rail with laser T markings along the top of the picatanny rail. No short cuts are taken in the manufacturing process of our receivers; we let this product speak for itself!