Traxxas 8196 two-speed conversion kit adds a high/low transmission range to the trx-4 sport. The kit contains all the parts required for the vehicle. Kit requires a 4-channel radio and receiver (sold separately). use Traxxas stock and hop-up replacement parts to get the most out of your Traxxas vehicles. This product is made from high quality materials and designed for long-lasting performance. This is replacement hardware for use on Traxxas vehicles; consult your user's manual for exact parts listings.