VERTEX 2-stroke pistons are gravity cast from an aluminum alloy with 18% silicon content. The added silicon reduces thermal expansion at operating temperatures, providing the advantage of making the piston less prone to rattling and breakage. Additionally, silicon enhances the wear properties of the piston, extending its lifespan. The kit includes the piston, piston ring(s), piston pin, and piston pin retainer! Piston variations for 2-stroke: Replica = piston corresponds to the original form, Race = performance-enhancing piston design, Pro Race = forged special piston.