Safer for Dog & People- Ultrasound will not cause any interference or harm to the human body. The ultrasonic frequency emitted by the ultrasonic barking controller is within the average hearing range of a dog. Other family members or neighbors will not worry about being affected. It does not cause major punishment to the dog, it emits an ultrasound that only dogs can hear to get its attention. 3 Adjustable Frequency-The Dog Barking Deterrent Device has 3 adjustable levels (15FT-50FT). Different dogs may be sensitive to ultrasound in different frequency bands. Please turn the knob to test different frequency bands for best results. If you or your neighbor's dog barks too excitedly, put it in the right spot, and you'll have a quiet resting environment. Durable & Waterproof- Dog Barking Control Device has IPX4 waterproof, the case is UV resistant and not easy to fade. Designed to be easily hung/installed on trees, walls or fence posts to stop any dog barking (within range), indoors, outdoors, etc. anywhere. The dog deterrent device is not suitable for aggressive dogs and hearing impaired dogs. Easy to UseAnti Barking Device has a built-in pickup that can detect the dog's barking within 50 feet and automatically emits ultrasonic that the dog can hear. Once the dog stops barking, the device automatically stops. Compared with the traditional dog training device, it completely frees your hands. Automatic and effective training your dog to stop excessive and noisy barking. Energy SavingOperates 9-Volt batteries (not included), average battery life 5-6 months depending on use. It can be started with a 9V battery (not included). Keep it at arm length, then whistle into the microphone. The device will beep and the LED will flash green.