- GFCI TEST BUTTON: This tester checks UK sockets for proper wiring and the GFCI trigger function. It tests the protection system to ensure household electrical safety and reduce the risk of electric shock. - Bright LED display: Light patterns are labeled on the back of the device. Green LEDs stay visible in bright sunlight, and a built-in light allows use in the dark for quick reading. - Easy to use: Large, readable error chart with 7 patterns: correct, ground open, neutral open, live/NEW reverse, live/GRD reverse, live open, live ground reverse missing ground. Provides a clear indication for quick understanding. - Wide application: Conforms to CE, FCC, and RoHS safety standards. A general measuring tool suitable for school, laboratory, factory and other settings, helping to diagnose socket problems quickly and efficiently. Use scenarios: - In schools or laboratories to verify outlet wiring before connecting equipment. - In factories or maintenance areas to check new or serviced outlets for proper wiring and grounding. - At home to confirm GFCI protection and identify wiring faults before use.