Piston Kit - 43.46 mm - Yamaha Gravity cast aluminum alloy with 18% silicon to increase resistance to wear and decrease thermal distortion, thus providing a longer piston life, Wrist pin is nitride-coated, providing a hardened, wear-resistant bearing surface, Coated skirt ease break-in, decreasing wear and aiding in lubrication, OE with OE compression ratio, rings are sold individually, Wear-resistant piston rings, Piston kit includes piston, rings, wrist pin and circlips