Uses two ways to repel a dog. Using the latest ultrasonic technology, the Dog Chaser produces an uncomfortable but not harmful, high frequency sound, audible to dogs but not to humans (20,000Hz - 25,000Hz). The second is a super bright LED flashing strobe thea temporarily blinds & confuses the dog. Help stop the approach of unwanted dogs at up to 15 feet. Also, a useful aid in training dogs (like the next door dog that won't stop barking...)