VERTEX 2-stroke pistons are manufactured using a gravity casting process from an aluminum alloy with 18% silicon content. Silicon helps to reduce thermal expansion at operating temperatures, which minimizes the risks of piston slap and breakage. Additionally, silicon enhances the piston's wear resistance, thereby extending its lifespan. The piston comes with a piston ring(s), piston pin, and piston pin retainer! Piston types for 2-stroke: Replica = piston matches the original design, Race = performance-enhancing piston design, Pro Race = forged special piston.