Features and Benefits * Test 4 and 5 pin flat connector wiring in 30 seconds * Each signal from vehicle emits a unique tone * Tester also emits unique tone for any shorts in the wiring * Simple to use, a one man tester Dont waste a lot of time when trying to test your trailer wires. This one man, 30 second tester greatly reduces time spent verifying vehicle trailer wiring. Its simple to use, just apply brakes, turn signals, running lights and engage reverse.