The VERTEX Piston Kit HONDA Pro Replica is crafted to withstand the increased cylinder pressure found in 4-stroke engines. The piston is manufactured from high-quality 2618 aluminum alloy to endure the internal pressure of the engine. Each VERTEX piston features a MOS2 coating on the piston skirt to reduce wear and tear. As an original equipment manufacturer for some of the major motorcycle brands, VERTEX is trusted by many factory teams within the MXGP for its superior performance. The kit includes piston rings, piston pin, and circlip. The 4-stroke piston comes in two versions: Pro Replica, which is a forged piston matching the original shape, and Pro HC, a forged special piston that provides higher compression and performance enhancement.