Bravo Company’s BCM KeyMod Picatinny 4″ Nylon Rail Section is made of Lightweight Impact Resistant Polymer. 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.