VERTEX 2-stroke pistons are cast using a gravity casting process from an aluminum alloy with an 18% silicon content. The additional silicon reduces thermal expansion at operating temperatures, making the piston less susceptible to rattling and fracture damage. Silicon also provides the piston with better wear characteristics, thereby extending its lifespan. The kit includes the piston, piston ring(s), piston pin, and piston pin lock! VERTEX offers different piston configurations for 2-stroke engines: Replica = piston conforms to the original shape, Race = performance-enhancing piston design, Pro Race = forged special piston.