Using the latest ultrasonic technology, the Super Dogchaser uses two ways to repel a dog. One is a discomforting but not harmful high frequency sound (20,0000Hz-25,000Hz), audible to dogs but not to humans. And, the second is a super bright LED flashing strobe that temporarily blinds and confuses the dog. Can be used as a flashlight. Also has a training setting. Requires one 9 volt battery (not included). Dimensions 4-3/4" x 1-3/4" x 3/4"