Using the latest ultrasounic technology, the SUPER DOGCHASER uses two ways to repel a dog. One is the discomforting but not harmful high frequency sound (20,000Hz-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. Helps stop the approach of unwanted dogs up to 40 feet. Also has a traning setting. Requires on 9 volt battery. Can be used as a flashlight.