The sliders are made of UHMW-PE (ultra high molecular weight polyethylene), a tough plastic with good strength, wear resistance and dimensional stability. It is more dimensionally stable than Nylon and used in many industrial ball bearing and friction reducing applications. The bolts are made of highest grade commercially available 12.9(177,000 psi in tensile strength). The brackets are made of solid carbon steel 80,000 psi in tensile strength (not 6061-T6 aluminum used by many of 42,000 psi). Rest assured that you are getting the best material commercially available.