Designed for repelling rodents, this device uses ultrasonic frequency, together with the added benefit of electromagnetic technology to protect an area of up to 2500 square metres. This is largely achieved by the electromagnetic frequency which transmits a signal through every electrical cable within a building. Any pests within 1m of these cables will be affected, also making this product very useful for driving rodents out from ceilings, roof spaces etc. Safe for use around children, cats and dogs. For indoor use only.