OEM Replacement and AMA ApprovedRestore that crisp clean power that your dirt bike or quad use to have with a new Piston Kit from Vertex. All pistons are heat-treated with a T-5 hardening and tempering cycle; piston skirts are coated with a high-tech molybdenum bisulphite for faster break-in time and increased piston life Piston kits include piston, rings, wrist pin and circlips Standard pistons and rings are OEM replacements Two-stroke piston kits made from gravity cast aluminum alloy (not forged) with 18% silicone content, which produces an extremely light but very strong piston Includes Piston, Ring, Pin and Clips Models Years GasGas MC50 2021+ Husqvarna TC50 2017+ KTM SX50 Mini 2009+ KTM SX50 2009+ Size "AB" 39.46 "CD" 39.47