This is a set of Touring Car Tire Warmers from Trinity. These warmers are used before the race to warm-up tires. Warm rubber provides better traction, similar to an actual racing car. It normally takes a couple of laps to heat up a set of touring-car rubber or capped tires enough to soften them for optimum traction, and the process takes even longer in cooler weather and at night. Trinity's tire warmers will warm up your tires, so you'll have great traction right from the starting bell. FEATURES: The warmers were designed according to the same simple principle as those used in Formula 1: wrap a warmer connected to a power source (these units operate at from 7.2 to 12 volts) around the tire, and it will make the tire softer and sticker. Also good for use on speedway cap tires and for drying traction additive on foam tires. INCLUDES: Four Touring Car Tire Warmers. COMMENTS: A 12 volt source will get the tires warmer than a 6 cell battery pack However, a 6 cell pack will be sufficient for most applications.