VERTEX 2-Stroke Pistons are gravity-cast from an aluminum alloy containing 18% silicon. The presence of silicon reduces thermal expansion at operating temperatures. This advantage minimizes the risk of piston slap and damage. Additionally, silicon imparts better wear characteristics to the pistons, thereby extending their lifespan. Each piston kit includes a piston, piston ring(s), piston pin, and piston pin circlip. 2-Stroke piston variants include: Replica = piston conforms to the original design, Race = performance-enhancing piston variant, Pro Race = forged specialty piston.