We developed The Anti Barking Dog CD™ in conjunction with Smith’s Dog Training Academy to help dog owners and neighbors of inconsiderate dog owners control barking dogs humanely. This anti-barking device is the best we have to offer with up to 300 feet or more of coverage depending on what type of sound system you use. Most of our customers find success using home stereo speakers, speakers connected to their computer, or a boom box. The dogs are irritated by the sound that the cd produces. This is only temporary since you will only use The Barking Dog CD™ for a short period until the dog is trained. Once the dog associates their barking with this unpleasant sound, the undesired behavior will stop. Tens of thousands of our past customers used to have one thing in common… barking dogs! Complete instructions included. Does not affect cats or other animals.