Advanced Socket Tester can help you check house wiring and connection polarity of socket, it can also use to test leakage tripping. It is a professional socket tester which rapidly detect whether the socket's wire connection is correct or not. With Rcd/Gfci test function, it is more practical and safe. Features: PORTABLE ELECTRIC SOCKET TESTER --- Advanced socket tester for rapidly detecting whether the socket's wire connection is correct or not. Compact size, light weight and convenient to use. With voltage backlight LCD display for testing voltage. PLUG & PLAY --- Designed with Rcd/Gfci Test Button, One Click to know the working state of the leakage protector. Perfect for protect your security against the risk of electric shock. BRIGHT LED DISPLAY --- Light patterns are well labeled on the back of the device itself. The Red LED indicators can be light up clearly even in strong sunlight also be used in the dark, making you read it fast. 6 LED LIGHT PATTERNS --- With 6 easy to read indicators to indicate the state of the socket, easy to judge: Correct, Open Ground, Open Neutral, Live/Neutral Reverse, Live/Ground Reverse, Live/Ground Reverse, Missing Ground. 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. Home improvement acceptance and safety inspectionIt saves you lots of time in testing problems with sockets. Packing List: 1 * Electric Socket Tester