Trailer Dr. is a portable air brake and electrical trailer diagnostic tool built for technicians who need fast, reliable testing in shops, yards, and mobile roadside environments. The smallest and most powerful tool in its class, Trailer Dr. delivers 30 amps of output in a 15.2 lb waterproof unit used by fleets, repair shops, and mobile service operators across the United States. A 7-way connection supplies power, while the unit connects to the trailer’s gladhand couplings for air testing. Manual controls or a wireless remote let one technician activate lights, supply air, and apply the trailer brakes without moving the trailer or accessing the cab.