Principle of anti-bark box: When the outdoor anti-bark stopper is within range of a barking dog, the microphone picks up the sound and the anti-bark stopper automatically starts and emits ultrasonic waves. Dogs can hear ultrasound, but humans cannot. The dog will stop barking because it associates its barking with this unpleasant sound. When the dog stops barking, the ultrasound will also stop. Effective range up to 50 feet: Our anti-bark device is designed to work in multiple modes, Mode 1: Range low (up to 15 feet); Mode 2: Medium range (up to 30 feet); Mode 3: high range. Range (up to 50 feet); Test set: Verify that the equipment is functioning properly. A variety of dog bark prevention ranges to meet different outdoor needs. Safe and friendly for pets and people: The ultrasonic silencer has been tested and proven safe for pets and plants, its precise pitch makes it effective only for dogs and has no effect on people or other animals, it can be used to stop your dog or neighbors from barking, or stop your dog from bark while camping, or train your dog not to bark. Durable and IPX5 Weatherproof: The bark box housing is made of high quality IPX5 waterproof material, so the Anti-bark device is not only durable but can work in all weathers. For outdoor use, simply hang it on the tree. with a belt A gate or rope fence is the best option to deal with barking dogs during outdoor activities. Easy to use: The bark control is easy to use, Simply install the 9 volt battery (batteries not included), set it to the correct mode and hang it on a tree, fence or other high place. The compact design allows you to hold the bark box in your hand when you go out without taking up too much space, easily solving outdoor barking problems.