PESTFree is an ultrasonic pest repeller (multi-animal deterrent) which emits a wide range of ultrasonic signals, and so deters more than one type of animal. For example, it deters Cats, Foxes and Martens from your property, protecting birds, flower beds and 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 and harmless to all species. Operates day and 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).