Produced from high quality 6061 aircraft aluminum on computer controlled milling machines right here in the US. Mil spec hard anodized for a long lasting finish. Slides onto the 512 dovetail and easily attaches with the six(6) supplied set screws that, unlike a 4 screw system, allows you to level the rail BEFORE you install your optics. No drilling or tapping required. Accepts Picatinny and Weaver style rings.