Each signal from vehicles emits a unique tone;Loud beep can be heard over shop noise;Apply brakes, turn signals, running lights, engage reverse and listen;Greatly reduces time spent verifying vehicles trailer wiring;Very simple and easy to use, saves time

• ESI 220 4/5 Pin Flat Trailer Wiring Buddy

ESI 220 4/5 Pin Flat Trailer Wiring BuddyElectronic Specialties