Each unit features reflective predator eyes to confuse and scare birds from coming near the protected area. The Repeller 360 degrees uses wind power to rotate continuously and covers a 6 diameter.Device uses wind power to rotate continuously and covers a 6 foot diameter,Ideal for use on boats, docks, AC units, signs, rooftops and other areas,Each unit features reflective predator eyes to confuse and scare birds from coming near the protected area