Lightweight and portable, this handheld dog bark control system stimulates dogs through sound that humans can t detect and won t hurt the auditory sensors of pets or other animals for safer daily training. This anti barking device can be used anywhere - jogging or walking, cycling, at the park, in the car, at the beach and so on , it is convenient to carry in your pocket. Can be used to prevent dog attacks, issue ultrasound to repel the dog or wild wolf. In normal situation, it can be used as a normal flashlight to illuminate at night. The first gear is a flashlight, the second gear is a Training dog, and the third gear is Drive the dog.(Please note:Don't use the third function for your beloved pet.