This purchase is for one set of clutch sliders that fit the models above. 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. Unlike our traditional center-hollow plastic pucks, the new pucks are completely solid and have up to 35 percent more surface area. This translates to a significant increase in strength. The gold spacers are made out of air-craft grade 6061-T6 aluminum and coated in a UV-resistant anodized finish. The bar is made of aircraft-grade stainless steel 304. Rest assured that you are getting the best material commercially available.