Bird-X Ultrason X Ultrasonic Bird Repeller, 4-Speaker Professional System Covers 3,600 sq ft Coverage #1 BEST-SELLING Ultrasonic Bird Repeller for outdoor areas Drives birds away from unwanted areas humanely and safely Effective and easy-to-use bird control Saves Outdoor Grounds from Bird Damage and Mess 4-Speaker System Covers up to 3,600 sq. ft.