We purchased the Bark Off Ultrasonic Training Aid and following the directions precisely. Our Yorkie was not fazed by it one bit. It is advertised to stop unnecessary barking. We placed it by the front door where she does most of her barking. It's plugged in to electricity; we also tried using a battery in the other one. Both are under a 5 to 10 ft. distance. A month has passed and there are no results! Please respond to this email. Thank you, Sincerely yours, Mrs. Leonard Rosenthal read full review »