When current flows, it triggers a relay contact as expected. I like that it has LEDs to show the switch status. It is the lowest cost unit of its type I have found. I'm using it on the hot side of a dishwasher's AC supply to trigger home automation. The initial 30 seconds of the dishwasher cycle are too low current to trigger this even at the lowest setting, but once it gets going the current is sufficient. Having the pot to adjust sensitivity is a nice touch. Overall very good so far!