Tekonsha part # 6562 is a 7-way blade tester and trailer emulator with LED display. It can be used to check the electrical continuity of all circuits in the 7-way blade style connecter. Plug the tester into any car connector and you can check the following circuits: running lights, left and right turn signals, auxiliary and electric brake, and battery charge. The 7-Way Trailer Emulator can also be used to properly install and setup a brake controller in the absence of an actual trailer. The 7-Way Blade Tester and Trailer Emulater with LED Display comes with a one year limited warranty.