Designed for residential & small area use, this low-profile electronic bird repeller uses quiet ultrasonic sounds to evict annoying birds from your deck, patio, balcony, or any other outdoor area around the home. The BalconyGard is a cost-effective, easy solution to your pest bird problem. BalconyGard utilizes ultrasonic sound waves to efficiently and effectively frighten, annoy, and intimidate birds and other wildlife within its 900 sq. ft. range. Birds don't like this at all and will stay away. Ultrasonic means that it is virtually "silent to humans", so you can effectively get rid of birds while maintaining a comfortable, enjoyable, bird-free environment for yourself.