Allows one person to test both male and female 7-round pin tractor-trailer plugs and more. In addition, the tester allows you to jump current to a dead circuit during emergencies so you can still drive your rig. Includes an extra jumper connector. It allows the jumping of current to a dead circuit for emergency situations so you can still drive the rig. Allows bypassing of malfunctioning circuitry while on the road Slides over 12V supply pin Winged tip for easier removal LEDs indicate that each circuit is working
