VERTEX 2-stroke pistons are cast from a gravity die in an aluminum alloy with 18% silicon content. Silicon reduces thermal expansion at operating temperature, which has the advantage of making the piston less prone to rattling and fractures. Additionally, silicon imparts better wear properties to the pistons, thereby extending their lifespan. The piston comes complete with piston ring(s), piston pin, and piston pin lock! 2-stroke piston versions: Replica, which matches the original form; Race, which is a performance-enhancing version; and Pro Race, a forged special piston.