Features:Electric Socket Tester - Advanced socket tester for rapidly detecting whether the socket's wire connection is correct or not.Design with RCD Test Button - Power outlet socket for correct wiring and RCD trip function. It can test the protection system to ensure the household electrical safety. Perfect for protect your security against the risk of electric shock.Easy to Use - Detect whether neutral, live and earth wire is connected correctly and to indicate which wire is missing with clear light patterns.Bright LED Light 3 Test Indicators - The light patterns are well labeled on the surface of the socket tester. The tester adopts a built-in light so it can also be used in the dark. Easy and fast to read the test result.7 LED Light Patterns - With 7 easy to read indicators to indicate the state of the socket, easy to judge: Correct, Open Ground, Open Neutral, HOT/Neutral Reverse, HOT/Ground Reverse, Open Hot, Live Neutral Reverse.Wide Application - Widely used for electric maintenance testing, office sockets testing, power strips testing and wall sockets testing in school, laboratory, factory and other social field. It saves you lots of time in testing problems with sockets.Portable Design - Compact size, light weight and easy to use.Note:1.Socket tester display Correct only means the pole is connected correctly, but does not mean resistance value is passed designation standard.2. Only passing Creeping Switch Test, it can finally obtain the earth resistance value to test whether the Protection System works well or not.3. To ensure your safety, don't make the insert out of shape to affect the test result. Forbid testing in public without permission.4. Turn off the electrical appliances before you checking the power protection systems to ensure no harms.