The VERTEX Piston Kit for Yamaha's 4-stroke engines is crafted to withstand the increased cylinder pressure typical of these high-performance motors. Each piston is forged from top-quality 2618 aluminum alloy, ensuring exceptional durability and strength to endure the internal pressures of the engine. To further reduce wear and enhance longevity, every VERTEX piston features a MOS2 coating on the piston skirt. VERTEX is a trusted original equipment manufacturer for some of the world's leading motorcycle brands. Many factory teams in MXGP also rely on the outstanding performance of VERTEX pistons. This comprehensive kit includes the piston, piston ring(s), piston pin, and circlips. For 4-stroke engines, the Pro Replica piston mirrors the original design, while the Pro HC variant is a high-compression, performance-enhancing piston.