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. Available is 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(TM) interface mounting surfaces. Test fit to ensure proper function (may display attributes consistent with this QC process) Please note: Nylon/Polymer Picatinny rail sections are for NON-load bearing accessories only. For load bearing accessories, we recommend aluminum Picatinny rail sections. Do NOT exceed 20 in-lbs. when securing KeyMod(TM) Fasteners on Polymer accessories. Aluminum Picatinny rail sections may be torqued to 30 in-lbs