Style: Modern Number of Pieces: 4 Is Electric: Yes Power supply: AC 90~250V Ultrasonic frequency: 20~65KHz Driving range: 15~30 Target Species: Cockroach, Mouse, Mosquito 1.The ultra sonic pest repell-ers emit frequencies ultrasonic interfering the auditory and nerve system of the pest, making them feel uneasy and uncomfortable so that pests, mice, rodents and mosquitoes away from your home. 2.The ultrasonic frequency of the electronic mosquito repellent is inaudible to humans and pets, environmental-friendly,The rodent repellent ultrasonic plug-in does not eliminate insects, but removes them from the covered area without using chemicals or smoke, which is an ideal choice for anyone who does not want to clean up for a long time. 3.Just plug the ultrasonic pest repellers into the socket. Please make sure to install it vertically 8-30 inch away from the floor. And make sure there are no barriers like curtains or cabinets covering in front of the ultrasonic pest repeller. 4.This rodent repellent indoor ultrasonic widely used in homes, warehouses, offices, gardens, hotels, etc. We recommend you to install one for each room because the ultrasound cannot penetrate walls and solid objects. But for areas with serious Vermin, we suggest install 2 or more pest repeller. 5.It usually takes 3-4 weeks for a different result depending on the amount of infestation.