How It WorK: worK by ultrasound waves which can irritate with the brain and auditory nervous systems to powerfully drive most types of pest Less Power Consumption: no need to clean up dead pests, no bad smell and Corpses, no battery required and save a lot of money Easy to Use: just plug the electronic pest control ultrasonic repellent in power socKets; it will start to repel the pests when the blue light on Wide Coverage: it is effective up to an area of 1600 SQ; put one in each room as ultrasound can not penetrate through walls and solid objects Quiet and effective: the ultrasonic insect repellent device using low frequency ultrasonic worK