This Megasonic Cat Repeller Stops Cats Fouling On Your Plot Or Menacing Wild Garden Birds So You Can Keep Your Plot Foul-free.ultrasound Noise Is Just Enough To Deter Cats Without Harming Them.dogs & Other Wildlife Will Not Be Affected By The Ultrasound Noise Either So You Are Safe In The Knowledge This Is Just A Feline Deterrent.the Pir (passive Infrared) Sensor Covers An Area Of Up To 40ft (120 Metres) With A 98° Arc., Sufficient To Protect An Average Vegetable Plot. The Coverage Area Is Up To 50% Bigger Than Other Models To Give You Superior Results To Other Models.included Is An Mounting Stake So You Can Install It Easily. You Just Need 2 X 9v Batteries Or 9v Adaptor & You’ll Be Fully Set Up.