The VERTEX Top-End Piston Kit for Honda Pro Replica is produced to withstand the high cylinder pressures typical of 4-stroke engines. These pistons are crafted from high-quality forged aluminum alloy (2618) to endure the internal pressures of the motor. Each VERTEX piston features a MOS2 coating on the piston skirt to reduce wear. VERTEX is a trusted original equipment manufacturer for several prominent motorcycle brands and numerous factory teams in MXGP rely on VERTEX's performance and reliability. The VERTEX Top-End Piston Kit is designed to save you both time and money, as it includes everything required for a piston replacement. The kit comes with a piston set, cylinder gasket set, and timing chain. Piston type for 4-stroke: Pro Replica = forged piston in the original form, Pro HC = forged special piston with higher compression for enhanced performance.