PESTFree is an ultrasonic pest repeller (multi-animal deterrent) which emits a wide range of ultrasonic signals, & so deters more than one type of animal. For example, it deters Cats, Foxes & Martens from your property, protecting birds, flower beds & lawns. When the PESTFree unit is triggered, bursts of ultrasonic sound are released, which results in the pests retreating from the protected area. Inaudible to humans & harmless to all species. Operates day & night in most weather conditions. Covers up to 88sq m. 2 year warranty. Proudly made in Great Britain. Power supply: 1 x 9 volt Duracell battery or, for increased performance use, the optional mains adaptor (20% louder sound).