The ultrasonic anti bark device is the most humane and effective way to stop unwanted barking. It is easier to use and safer than electric dog collar. The anti bark device can detect dog barking and automatically emit ultrasound to stop unwanted barking, more intelligent and effective. Problems with use It is not recommended: 1. The anti bark device will not work on hard of hearing or aggressive dogs. 2. Not recommended for dogs under 6 months and over 8 years old. 3. It is not recommended to use a single device against two or more barking dogs at the same time. Warm Tips: 1. Make sure the bark controller is in clear range in front of the dog. 2. The maximum detection range is 15 meters, the bark stopper will not activate when the dog barks if it is out of this range. 3. It is not recommended to use the same ultrasonic frequency on the same dog for 10 days or more. The dog may have resistance to the same frequency. Please change the frequency every 7-10 days. Ultrasonic Control - You