100% SAFE AND HARMFUL: The anti-bark device adopts high-pitched ultrasonic technology, which will not cause any harm to humans or dogs. But it can easily grab the dog's attention and stop the dog from barking continuously and excessively. Automatic and Convenient: Compared with traditional dog training collars, this dog bark deterrent device can automatically detect dog barking, emit ultrasonic waves and stop ultrasonic waves, which will completely free your hands to stop your dog or neighbor's dog barking. Our bark preventer is a humanized ultrasonic bark control device that helps to control excessive barking and abnormal barking of dogs, it automatically detects the barking of dogs, and then emits a safe and harmless ultrasonic wave to stop the dog barking. Bring you a quiet and comfortable rest learning environment! main feature 1. Automatically detect dog barking and send out ultrasonic waves to stop dog barking. / Automatically stop ultrasound when the dog stops barking. 2. Durable, waterproof, smash-proof, sturdy, weatherproof material. Note: Please bring your device home when it rains heavily 3. Small size, light weight, easy to install, place or hang anywhere. 4. Maximum effective range up to 33 feet. 5. Suitable for all breeds and sizes of dogs. 6. Size: 8.5*7.5*10CM Notice 1. Not recommended for dogs over 50 lbs. 2. Not recommended for dogs under 6 months and over 8 years old. 3. Not recommended for hearing-impaired, grumpy or aggressive dogs. 4. Not recommended for use in particularly noisy environments. 5. It is not recommended to use 1 device with 2 or more dogs at the same time.