Safe, effective supersonic rodent repeller uses sound waves to keep burrowing animals away from your garden - without dangerous poisons or chemicals. Sonic rodent repeller has high-pitched 15-second sounds are intolerable to moles, squirrels, gophers, and shrews. Ultrasonic rodent repeller uses four D batteries (not included). Protects up to 500 square. yards. Plastic; 13 1/2" high.