Automatic Barking Control The device intelligently captures barking dogs up to 15 meters away, and automatically emits ultrasonic waves to distract your dog, stop unnecessary barking, and allow you to enjoy a "moment of peace and quiet" ". Dog Bark Stopper Ultrasonic frequencies are harmless to pets and completely inaudible to human ears. If the dog is hard of hearing or aggressive, the device may not work as expected. It is not recommended to use one device at the same time to deal with the barking of two or more dogs. 3-level operation Adjustable frequency bark deterrent for different dogs. 15KHZ-30KHZ is suitable for big bad dog. 20KHZ is suitable for gentle dogs. 30KHZ is suitable for small dogs. Recommended for dogs 6 months to 8 years old. Rechargeable via USB The ultrasonic dog repeller contains a rechargeable lithium battery, the device can work continuously for 30 days after being fully charged within 5 hours. The red/blue color indicates battery status. Easy to install and waterproof The bark stop can be hung on a tree, wall or fence to prevent your own dog or neighbors from barking. Make sure the barking controller is facing the dog, within easy reach and without any obstructions. Note: The Ultrasonic Bark Stop uses sound waves to stimulate the dog to stop barking. This product is affected by the outside world (noisy environment) and sometimes does not work properly. Not all dogs work, such as aggressive dogs, military dogs. This is also a defect of all ultrasonic bark stop products. When the product is turned on, the blue light is on