Bark Stop Classic, Bark Free Dog Silencer & Animal Pest Repeller, Ultrasonic Bark Deterrent - Yard Sentinel Dual Brand new version of the famous Ultrasonic Pest Repeller with a specially designed Bark Stop feature! Silent to humans, permanent solution for dogs, cats, rodents, raccoons, skunks, insects, squirrels, birds, bats, deer, etc. Weather-resistant. 24-hour activation. Easy to operate, easy to mount using keyhole slots. Ultrasonic emitting selection: Motion Sensor / Constant / Bark Stop modes. 2014 Model. AC or battery powered. AC adaptor & free 33 ft. (10 m) extension cord included.