Bark Free Ultrasonic Trainer LT I6I Sharper Image Constant Barking triggers a harmless ulrasonic tone that is designed to quiet your own or a neighbor's dog. Mounts to a wall with the included bracket. Use indoors or outdoors with the included Rain Cover. The UlraSonic tone is not audible to humans but can be made audible. Also, the sound sensitivity is adjustable. The UltraSonic dog trainer plugs into an AC outselt with the included 50 foot extension cord. What Results to Expect? Protective Barking(may bark at trespassers or neighbors that tease or threaten them. This may include people knocking at your door or people walking through your yard)-Dogs trained to Bark(may inadvertently be trained to bark, by receiving attention(both positive and negative)for barking-Feeding time and work time Barking(we recommend that you disconnect Bark Free when feeding. When walking one dog and leaving others behind, get out of sight as soon as possible)- Hearing Problems(deaf dogs will not react to Bark-Free)-High Stress Environments(Is not recommended for boarding kennels, animal shelters, and grooming salons. These locations generate protective and fear barking)