No Bark Indoor Outdoor Bark Control helps you to control your dog's excessive barking or even your neighbor's dog in a humane way that actually teaches the dog not to bark. Sends out an ultrasonic signal that only dogs can hear when the barking begins. Dogs quickly learn that their barking causes this irritating sound and that stopping the barking stops the sound. Features variable sensitivity adjustment. Works on any breed and has a range of 30 feet. Comes with an AC adapter and easy-install bracket that allows you to position and optimize to the location/direction of the barking. If used outdoors, must be placed under a covered area.