I was tasked by my wife to rid her garden of the voles. Unfortunately, this is not the device for that task. Our Garden is very small at approx 150 sq ft. We purchased one of these and placed it in the center. Even though the unit appears to be operating correctly, the voles are tunneling within 4 inches of the unit. They don't seem to be affected by this unit. Our neighborhood cats have delivered 4 voles to my driveway in the last month. Maybe i need to stick to feeding the cats.I give it two starts just for the fact the unit was received in a well packaged box with very quick shipping.