Balcony Guard Ultrasonic Bird Repellent 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. Motion activated Bird Deterrent 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. Bird-X Balcony Guard mounts anywhere with keyhole slots. 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).