SBT Polaris jet ski pistons 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 Polaris 650 Piston Kit 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.