0mpilchfamilyBest Answer 6 years ago That is an electronic pest deterrent device with built in night light. It emits high frequency audio which is suppose to be above human hearing but within the range mice, rats and bugs can hear. The idea being it will annoy them enough that they will stay away. Truth is these things don't work. Insects could care less. When first plugged in it may scare off rodents but they will get use to the sound and ignore it after a while. So it' has the frequency and pitch adjustments to try and change things up but it's only temporary at best.