Deck-Guard DGULTRASONIC Ultrasonic Bird Repeller Ultrasonic Bird Repeller: For Use on Recreational Boats Solar Powered with Motion Sensor protects up to 30 feet Weatherproof: Sleek, weatherproof casing is designed to withstand years of outdoor use. Maintenance-Free: When installed properly, no ongoing maintenance is required DeckGuard units come with our 30-Day money-back guarantee