Vertex Long Rod Piston Kit - 1.00mm Oversize to 64.95mm 23607100As the OE supplier of two stroke pistons to KTM, Vertex pistons has an outstanding reputation for quality and performance. Each gravity cast piston is created with only premium aluminum alloys utilizing an 12 21% silicon content. The silicon content in Vertex pistons is crucial to the quality of the piston. Silicon is critical in decreasing thermal expansion which, when an engine reaches normal operating temperatures, can change the geometry of the