Manufactured by Namura HyperDryve Series piston Kit Includes piston, rings, pin, clips you get exactly what is pictured The HyperDryve line of pistons is composed of a space-age hypereutectic aluminum alloy developed by NASA. Engineered to maintain its high tensile strength up to 700 F 370 C , 50% higher than a conventional cast piston, this gives HyperDryve pistons the strength to perform under operating conditions normally reserved for forged pistons. Piston skirts are Molybdenium Teflon coated to minimize resistance/wear and provide extended life. Also allows for smoother start-ups break-ins. Piston dome is anodized for superior heat resistance and longer lifespan Kit is for standard bore size 97.00mm Size A piston is 96.95mm 12.5 1 Compression ratio Made in Taiwan Fits 2010 Yamaha YZ450F 2011 Yamaha YZ450F 2012 Yamaha YZ450F 2013 Yamaha YZ450F