Silent Bird Repeller safely keeps birds away from areas around your home. Rid areas from bird messes and more, with Bird-X. around your porch, patio, balcony, pond or pool area. Silent Bird Repeller emits a powerful sound only birds can hear. Ultrasonic sound amplification is adjustable, so you can set it effectively so that the birds stay away. Silent Bird Repeller mounts anywhere with keyhole slots. Silent Bird Repeller has A 16' detection range. Unit measures 6 ½”L x 5 ¼”H x 3 3/8”W, and requires 4 "C" batteries (not included) or runs on 120 V AC adapter with 54' cord(included).