The VERTEX Race Evolution Piston is specifically developed for racing use and is the ultimate performance weapon among all pistons. VERTEX 2-stroke pistons are cast using a gravity casting process from an aluminum alloy that contains 18% silicon. The inclusion of silicon reduces thermal expansion at operating temperatures, resulting in a piston that is less prone to knocking and breakage. Additionally, silicon enhances the wear resistance properties of the piston, thereby extending its lifespan. The VERTEX TopEnd piston kits include everything you need for a piston replacement (piston, piston rings, piston pin bearing, circlips, etc.). VERTEX is an original equipment manufacturer for some of the largest motorcycle producers, and many factory teams in the MXGP trust the performance of VERTEX products.