How it Work: this electronic pest repeller works through ultrasound, irritating the pest’s brain and auditory nervous systems, so as to repel most types of pests away effectively Effective Coverage - Effective Coverage in indoor area up to 1200 sq feet.Recommended to install this device from 8-27 inches away from the floor.Apply in houses, office, apartment, supermarket, warehouse, hotel or other place. More Safe for Child ; Pets - Ultrasonic sound is inaudible to humans and household pets,environmental friendly alternative to dangerous poisons and Sprayers, chemicals and traps, no bad smell and Corpses Easy to Use: - Pest repellents are simple to use. All you do is plug pest repellent ultrasonic in an electrical outlet and it will start to repel the pests when the blue night light is on. The repeller should be placed in a location where its noise will not be affected by walls and furniture. It is recommended to install this pest repeller between 30-50 inches away from the floor for