This is an optional Traxxas Aluminum GTR Shock Set, and is intended for use with the Revo, E-Revo, Summit, Slayer, and Jato trucks. Whether you’re looking for the ultimate in damping performance and consistent lap-after-lap control, or you want to customize the look of your truck, these GTR shocks are the perfect addition to your model. The GTR design features a machined, threaded aluminum body with an oversized spring collar for easy and precise preload adjustments. The spring perches are vented to help prevent dirt from packing around the X-ring seals, and hard-chrome shafts resist stiction for smooth action and consistent performance. Inside the shock, volume-compensating bladders are used to ensure perfect damping throughout the travel range. Red- and blue-anodized GTR shocks are sold fully assembled in sets of four complete with silicone fluid. The anodized aluminum bodies are also available separately and are a direct fit for all GTR shocks. NOTE: These shocks do not include shock springs. Features: Precision-machined threaded aluminum bodies Vivid red or blue anodized finishes Premium-quality silicone shock fluid Oversized, easy-to-turn preload collars Exclusive X-ring seals for better sealing with less friction