Namura Top End Repair Kit + 1MM Bore NA-50025-4K fits 2003-2013 Polaris Trail Boss 330 / 2008-2013 Polaris Trail Blazer 330 / 2003-2005 Polaris Magnum 330 2X4 / 2003-2006 Polaris Magnum 330 4X4 / 2004-2005 Polaris ATP 330 4X4

Top End kit includes: piston, rings, wrist pin, clips, top end bearing, and gasket kitMOS2 (Teflon/Molybdenum) Coated Skirts A rolled on application process provides a bond that is 10 times stronger than other spray on coatings. Benefits include increased heat transfer, reduced friction and helping to eliminate cold seizuresMachined Smooth Heads Reflects combustion heat and reduces carbon buildup, protecting the top of the piston. Some tests have shown this feature can increase horsepower and fuel economy by up to 6%Anodized Domes Increases heat resistance and durability; pistons with anodized domes are 75% stronger than non-anodized pistonsHypereutectic Casting Process Provides higher silicon content for reduced expansion rates and additional wear resistance; it also has an ability to withstand higher cylinder temperatures