Wiseco RC899M09550 Racer's Choice 13.5:1 Compression Ratio Piston Kit ArmorGlide skirt coating for reduced friction and improved wear and horsepower ArmorPlating coating in ring groove to eliminate micro-welding and improve wear ArmorPlating on dome protects piston from detonation Titanium Nitride coating ring for improved seal and wear DLC Coated piston pin for improved wear and performance