As Master, I have my computer, which turns on at start-up screens, printers, etc. with. In idle state, the Green round LED lights and toggle switches. Once the set power is (in my full rash) exceeded the yellow LED comes on together with the other outlets. Is directly after the PC switched everything off again.
All three LEDs are very dark, so not at all disturbing. The processing is despite "Made in PRC" (Peoples Republic of China) properly.