Humanized Dog Training AidUnlike other impact dog training tools, our ultrasonic bark control device provides a user-friendly, safe and effective solution to help owners control unnecessary barking and correct bad dogs Behaviors such as eating unsafe food, biting, digging, fighting, etc.Effective Dog Barking DeterrentOur anti-bark device has a control range of 16.4 feet, our anti-bark device uses the latest ultrasonic technology with a frequency of 25KHZ. The sound doesn't affect humans (the audibility is limited to 20KHZ), but it can easily grab the dog's attention and improve their bad behavior. Continued training is required for effective and lasting results.Suitable for All Sizes of DogsOur handheld anti-bark device can be used for dogs from 6 months to 8 years old. With the frequency button, you can easily adjust the ultrasonic frequency according to the condition of the dog.[Adjustable in 2 gears, suitable for different purposes] standard frequency is suitable for indoor training, outdoor use needs to strengthen the frequency.Tips 1. Pull down the back cover of the battery forcibly. 2. Put the battery (not included) on the strap so you can pull up on the strap to remove the battery.