The Self-test SmartlockPro Slim GFCI (ground fault circuit interrupter) guide light is a great way to add an extra element of safety when it is dark without losing outlet space. The device offers dual LED (light emitting diode) guide lights that turn on and off automatically based on light levels and uses only 1-watt of electricity. Designed to meet the latest UL (Underwriter’s Laboratories) standard for auto-monitoring (self-test), periodically conducts an automatic internal test to confirm that it can respond to a ground fault. Slim profile, fast and easy installation, and patented reset lockout mechanism that prevents reset of the GFCI if it is not wired or operating correctly. Monochromatic, back and side wired, self grounding clip included. Wall plate sold separately.