Rail section is made of Hard Anodized Aircraft Aluminum Alloy. Mounting hardware is made of Corrosion Resistant Stainless Steel Made to the Mil-Standard 1913 Picatinny Arsenal Specifications. Made in three Lengths: 3-inch (5 slot), 4-inch (7 slot) and 5.5-inch (11 slot) Features a Snag resistant design, while retaining Mil-Standards specs. Self-contained assembly, eliminates the possible loss of mounting hardware. Fits ALL KeyMod interface mounting surfaces.