The VERTEX 2-Stroke Pistons are cast using gravity die casting from an aluminum alloy containing 18% silicon. The presence of silicon reduces thermal expansion at operating temperatures. This feature means the piston is less susceptible to knocking and damage. Additionally, silicon imparts better wear characteristics to the piston, thereby extending its lifespan. The piston kit includes piston ring(s), piston pin, and piston pin circlip! VERTEX offers various 2-stroke piston designs: Replica = piston matches the original shape, Race = performance-enhancing piston design, Pro Race = forged special piston.