Keeping Deer out of your yard has never been easier – the Deer Gard Electronic Animal Repeller uses ultrasonic (silent to most humans) sound waves to keep deer far away from its perimeter. The Deer Gard eliminates the need for messy and expensive chemicals and saves money on plant and yard damage. Fully equipped with a motion sensor, the Deer Gard can be set to either go off only when deer come into its range, or set to constant to prevent deer from entering the wider area.