Bravo Company's BCM KeyMod Picatinny Aluminum 4 inches 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. Features: 4 inches rail section - 7-slot Fits all KeyMod interface mounting surfaces Fits AR rifles