Special feature = The pucks are solid and not hollow, made to withstand a greater impact. Brand = T-Rex Racing Material = UHMW-PE (ultra high molecular weight polyethylene) and aircraft grade aluminum. NO CUT or plastic fairings modification required. Fit Models = KAWASAKI 2017 Z900 / ABS This purchase is for a set of frame sliders for the above bike model. The sliders feature a new design of a complete solid puck without a hollowed-out center. This increases the strength and contact surface to about 30%. The bracket is bolted to the engine mount and the slider puck is bolted onto it. The material of the puck is 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. Compared to Delrin, it is softer but tougher. Delrin is harder but more brittle. It is an ideal material for frame sliders since it can absorb more impact force onto itself and therefore reduce the impact on the frame and engine. The slider pucks can be inexpensively replaced in case of a low-side. We use highest grade commercially available 12.9(177,000 psi in tensile strength) wherever possible. Rest assured that you are getting the best material commercially available.