This duplex receptacle comes with green and red LED indicators that show the condition of the outlet. The green light shows that the device is properly working, while the red light blinks regularly as a sign of self-test to notify that the GFCI is continually working. The red LED also lights up once the outlet can no longer provide continuous ground fault protection.
In case you want to perform manual tests on the outlet, you can press the TEST button right on the device`s surface. Also, unlike fuses, you can always reset the GFCI once it trips off using the RESET button. These switches are necessary to keep your electronics safe and in a good state.