WorkPro GFCI Outlet Circuit Tester detects common wiring problems in standard and GFI outlets. To test an outlet, simply plug the tester into the outlet and read the test lights. A test button helps to determine correct operation of a GFI receptacle.It is easy to carry and can easily test whether your socket is safe. It can easily test whether your socket is safe, and it is a good helper for the electrician。Made of superior and durable materials, the service life is longer.The function is powerful, and there are many types of faults that can be tested.The following faults can be detected: open circuit of neutral wire, open circuit of live wire, open circuit of ground wire, reverse connection of live wire and neutral wire, reverse connection of live wire and ground wire, reverse connection of live wire and ground wire without ground wire, and detect leakage protector.