This is a set of optional ST Racing Concepts Aluminum Caster Blocks for Traxxas Slash, Rustler, and Stampede vehicles, as well as the Nitro Slash. With the popularity of the "Monster Energy" paint scheme, and the release of the Traxxas Monster Jam replica Grave Digger truck with green chassis components, STRC has stepped up and are now offering their popluar CNC machined aluminum components in green to help customize any green themed rig. Using high quality CNC machined aluminum, these aluminum caster blocks greatly increase the strength of the front suspension of your car or truck.