Drive rodents away, without poisons, traps or sprays. The Pro Pest Repeller is a plug-in device that uses electromagnetic technology to emit digital pulses via your walls wiring. These pulses don"t bother pets or people, but critters can"t stand them and leave the premises. Use one unit per floor. Dual use device also has a built-in night light and on/off switch. 2.25 x 1.75 x 4 inches.