The RPM ESC Cage for both the Castle Sidewinder 3 & Sidewinder SCT ESCs fits in the stock location on the Traxxas Slash 2wd, Slash 2wd LCG, Slash 4x4, Slash 4x4 LCG, Stampede 4x4 & Rally, while also working on other Traxxas 1/10th scale vehicles as well. RPM's cage allows the ESC to be run with or without a fan. It encases the ESC body only, leaving the entire ESC fan free to do its job. Furthermore, they left air channels along the sides of the ESC to allow air movement along the sides of the case, helping to keep the ESC cool. Each ESC Cage is designed to simplify ESC installation and maintenance of the vehicle. Two screws hold the entire assembly to the chassis, that's it! No more struggling with gooey double-sided tape to remove the ESC to clean your vehicle or transfer the electronics to another car. It's so quick, you can transfer the entire assembly from one vehicle to the next in about a minute! We include a separate, encased on / off switch mount that bolts directly to our cage in one of four locations / orientations for extreme versatility. Since the switch attaches to the cage, no extra time is needed to remove it during maintenance or if you decide to swap the ESC between vehicles. Alternately, you can mount the switch anywhere you'd like simply by drilling and tapping two 2mm holes.