WISECO PISTON KIT YZ250 STD W808M06640Endurance and high rpm, Each piston is electra coated on the dome, ring groove, and pin bore, for maximum wear resistance and protection from micro welding, galling and detonation, GP Series parts generally have less machining on the outside, which helps seal up the bore for increased compression, ArmorGlide skirt coating reduces friction and noise for more horsepower potential, Kit includes piston, ring(s), wrist pin and circlips, Engineered, forged,