Piston Kit Namura YZ250 99-21 YZ250X 16-21 1.5mm oversize 67.85mmFeatures:Machined smooth piston crown to reflect combustion heat while reducing carbon buildupHard anodized piston crown with a hardness of HRB 105MOS2 coating to draw heat through piston walls and out the bottomMinimized piston expansion and contractionPistons are more resistant to wear and scuffing, expand less with heat and are strongerHigher Performance piston without a higher priceCarefully developed for the highest level of qualityUnsurpassed in functionality and reliabilityReady to serve reliably for years to comeIncludes:PistonsRingsCirclips