VERTEX 2-stroke pistons are gravity cast from an aluminum alloy with an 18% silicon content. The silicon reduces thermal expansion at operating temperature. This results in the piston being less prone to rattling and breakage. Silicon also provides the pistons with better wear resistance, thereby extending the piston lifespan. The kit includes piston(s), piston ring(s), piston pin, and piston pin circlip! 2-stroke piston variants: Replica = piston corresponds to the original shape, Race = performance-enhancing piston design, Pro Race = forged special piston.