Plug In: Please install our item at 7-16 inches away from the floor . Just plug our electronic mice repellent into the socket and should be vertical to the floor.Usually repellers take 3-4 weeks to make effect. Wide Effective : The Ultrasonic Pest Repellent is effective for an area up to 800- 1,200 Sq. Ft.Since ultrasonic sound cant penetrate wall, one room one unit is recommended.. Mild Humming Sound: The waves that this repeller sends are far beyond the hearing range of human-beings. The machine produces mild humming sound for pest repelling function. Safe & Economical: Discard your harmful chemical repellent.The electronic pest repeller is safe for pregnant woman and baby , Odorless, noiseless and no radiation. Pest control uses ultrasonic frequency sound waves to drive pest and rats away without killing them. Repel Lizard,Rats, Cockroach, Mosquito, Home Pest & Rodent Repelling Aid for Reject Ants Spider Insect Pest Control Electric Pest Repelling Discard your harmful chemical repellent.The electronic pest repeller is safe for pregnant woman and baby , Odorless, noiseless and no radiation. Pest control uses ultrasonic frequency sound