Dog Bark Controller -- Avoid excessively annoying barking of dogs around you or your neighbor's. It is waterproof and Durable. Work By Ultrasonic -- Stops a dog from barking by emitting harmless high-pitched ultrasonic sound which can be heard by dogs as far as 50 feet away but is completely silent to human ears. 3 Range Level -- Detects dog barks up to 50 feet with the use of an internal microphone and 4 levels of operation including a test mode. Easy to install -- Hanging or mounting on a tree,wall or fence post to keep your own dog or your neighbors dog from barking. Make sure the microphone is less than 5 feet high and is facing the direction of the barking dog. Customer Guarantee -- We provide worry-free 18-month warranty and friendly customer service.If you have any questions about our anti bark control, please contact us and we will try our best to help you!