This purchase is for an engine case cover slider that helps protect your bike's engine case cover in the event of a low-side. It is made of UHMW-PE (ultra high molecular weight polyethylene), a tough plastic with good strength, wear resistance and dimensional stability. It is more dimensional stable than Nylon and used in many industrial ball bearing and friction reducing applications. It can be inexpensively replaced in case of a low-side. The bolts are made of highest grade commercially available 12.9 (177,000 psi in tensile strength. Rest assured that you are getting the best material and fully thought out product