An ultrasonic dog trainer that emits harsh ultrasonic waves that dogs hate. With it, you can train your pet to be obedient, correct inappropriate behavior, and stop barking. Humanized design, safe for people and dogs. Features: It can be used to train dogs, effectively help dogs to be obedient, correct inappropriate behavior, and stop barking. It emits harsh ultrasonic waves that dogs hate, repels hostile dogs, and prevents dangerous dog attacks when walking, jogging or cycling. It can also be used as a flashlight at ordinary times, which is very convenient to use. It is safe and effective for most dog work and does no harm to humans and animals. Equipped with an easy-to-carry lanyard for easy portability. Note: The device will fail in the following cases: 1. Your own pets, who knows you won't hurt them; 2. When the environment is too noisy, such as downtown or a busy sidewalk; 3. The dog protected by the owner is around. 4. A trained dog is familiar with these types of equipment; 5.