SBT jet ski pistons for Sea-Doo are high quality, high strength, cast eutectic pistons. Our "standard" pistons are comparable to others premium pistons - anodized on the top surface for better heat resistance and surface strength, graphite coated on the sides to reduce friction between the piston and cylinder and enable efficient break in. SBT is so confident in the quality of our pistons that all pistons come with a LIFETIME warranty against manufacturers defect! The Piston Kit for Sea-Doo 657/657X comes with our piston, complete set of steel rings, cir-clips, and piston pin - everything you need for swapping out a piston in your engine. Please choose the size you need.