Electronic Ultrasonic Mouse Rat Rodent Repeller - covers 150sq meter / 1600sq feet open space (ultra sonic frequency will not go through walls) - output frequency 20-55kHz - W 3-5/16" x H 3-7/8" x D 1-5/8" - brand new, never been used - $20 firm PRODUCT OVERVIEW: Emits high-frequency ultra-sonic sound waves to create an acoustically hostile environment and repel rodents. Ideal for environments where the use of poisons is inadvisable or prohibited. Will not harm humans or non-rodent pets. Perfect for kitchens, garages, attics, basements, warehouses, restaurants, etc. Plugs directly into a wall outlet.