Top End Piston Kit - 77.96 mm - Honda CRF250R/X The piston is heat-treated with a T-5 hardening and tempering cycle, The piston skirt is coated with high-tech Molybdenum Disulphite to allow faster break in time and increased piston life, Forged piston kit is forged from 2618 aluminum, Forged replica piston is a forged OEM , Top-end piston kit includes piston, rings, pins, circlips, top-end gaskets and cam chain