☀ Design with RCD/GFCI Test Button - Power outlet socket for correct wiring and RCD/GFCI trip function. It can test the protection system to ensure household electrical safety. Perfect for protecting your security against the risk of electric shock. ☀ Bright LED Light & 3 Test Indicators - Detect whether neutral, live and earth wire is connected correctly and to indicate which wire is missing with clear light patterns. 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, Live/Neutral Reverse, Live/Ground Reverse, Open Live & Live Neutral Reverse. ☀ Voltage Tester Pen - Dual sensitivity AC voltage range of 12V～1000V & 48V～1000V with switching S button. Detect AC voltage by contacting the power socket or getting near the live wire with a non-contact tip. ☀ Easy to use - With flashlight, convenient to use at night or dark corners. Breakpoint checking, live wire measurement and full wire measurement. Automatically turn off when no operation and no detection of AC voltage after 3 minutes.