What is GFCI Replacement Plug? 1) This attachable safety GFCI Plug earth leakage protection device is widely used to replace the general Plug of your power tools and home appliances, such as pressure washer, hair blower, hair dryer, vacuum cleaner, air conditioner, bathroom heater, aquarium, pool pump and all the Christmas cards that plug into each other. 2) It will trip off when it detects current loss, to protect people from electric shock. How to Test? To test if the GFCI plug works normally for electric leakage, please follow the steps below: a) Remove the GFCI plug from your electrical device. b) Plug the GFCI plug itself into a regular outlet and check if the green indicator light is ON. c) Press the TEST button and check if the green indicator light is OFF. d) Press the RESET button and check if the green indicator light is ON. If the GFCI plug passes the test, then the GFCI plug is working to protect you. When the GFCI plug keeps tripping after power is restored, there might be a risk of electric leakage for your electrical device, and the GFCI plug will shut down the power immediately and protect people from possible electric shock hazards. For your own safety, please kindly contact professional electricians and resolve the electric leakage.