Rail section is made of Lightweight Impact Resistant Polymer. Mounting hardware is made of Corrosion Resistant Stainless Steel Available it three popular colors: Black, Flat Dark Earth and Foliage Green 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. 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 Test fit to ensure proper function (may display attributes consistent with this QC process)