Vktech Ultrasonic Dog Chaser Stops Aggressive Animal Attacks Deterrent Repeller 100% Brand New and High Quality 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 Ultrasonic wave reaches up to 130db. Audible to dogs but not to human Effectively target animals up to 20m away