Bravo Company’s BCM KeyMod Picatinny Aluminum 4″ Rail Section is made of Hard Anodized Aircraft Aluminum Alloy. The mounting hardware is made of Corrosion Resistant Stainless Steel and made to the Mil-Standard 1913 Picatinny Arsenal Specifications. It features a Snag resistant design, while retaining Mil-Standards specs. The self-contained assembly eliminates the possible loss of mounting hardware. Fits all KeyMod interface mounting surfaces.