Namura +010MM PISTON KIT NA-50090-B fits 2012 Polaris RZR 4 XP 900 / 2013 Polaris RZR XP 4 900 / 2011 Polaris RZR XP 900, RZR900 / 2011, 2013 Polaris RZR XP 900 LE / 2012 Polaris RZR 4 XP 900 LE EPS, RZR XP 900 LE EFI / 2012-2013 Polaris RZR XP 900 EFI

MOS2 (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