Your home is your sanctuary! Keep it comfortable and rodent-free with the Bell + Howell Ultrasonic Pest Repellers Complete Home Kit. They use variable ultrasonic frequencies that are audible to only insects and rodents (not to humans or pets) to repel vermin from entering an area up to 120 sq. ft. Easy to use ­ Just plug the units into an outlet. Kit comes with 6 units: 2 small units that fit on small countertops or in corners; 2 medium-size units for living rooms or play areas; and 2 larger units with an extra outlet.Manufacturer model #: 50102. Uses variable ultrasonic frequencies to repel insects and rodents Not audible to humans or pets Protects an area up to 120 sq. ft. Easy to use just plug the units into an outlet Includes 6 units: 2 smaller units, 2 medium units, and 2 larger units