1. Correct the dog's bad behavior. This ultrasonic bark stopper can be used as a training tool to help train dogs to be obedient and develop good behaviors. 2. Lightweight and portable. This bark stopper is small and lightweight, which can fit perfectly into a pocket and comes with a wrist strap for easy carrying. 3. Suitable for dogs of all sizes (except dogs under six months old and aggressive dogs). 4. Press the button, and the bark stopper starts to work. The effective range is 5 meters (16.4 feet). All dogs within the range will hear the ultrasonic sound and move. 5. The green light will go out 10 seconds after pressing the button, and the bark stopper will also turn off. 6. Dog training aid. This ultrasonic bark stopper can effectively train your dog to stop bad behaviors, such as excessive barking, digging, chasing, eating dirty things or fighting. 7. If you are troubled by your dog's bad behaviors, such as stopping in front of passers - by, defecating in the open, eating dirty food, taking food from strangers or fighting, you need this ultrasonic bark stopper and training tool. 8. This dog trainer is an ideal choice for gently controlling a dog's barking. When excessive barking causes trouble, the ultrasonic bark control device is one of the gentlest ways to immediately catch the dog's attention - it can stop the dog from barking immediately without causing any harm to the dog. 9. Notes: - This product may not work for dogs with hearing impairments. - Do not use it on dogs under 6 months old. - It is not suitable for dogs with strong defensive aggression. - Keep it 30 centimeters (12 inches) away from human ears when using. - Different dog breeds may react differently to ultrasonic waves. - For the best results, use this product as a training tool along with other tools/commands. Be patient during the training process. - Build a relationship with your dog before using this product. - Reward your dog when it calms down and guide it positively to improve the dog's memory. Train and correct patiently.