If your beloved dog’s barking has become a frustrating reality for everyone within hearing range, the PetSafe® Indoor Bark Control - Multi-Room can help you reduce the noise. It uses a high-pitched tone that’s triggered when your dog decides to speak up. The ultrasonic tone is inaudible to most humans but is annoying to dogs. they'll quickly learn to associate their barking with the unpleasant sound. Our two small, portable units detect barking in areas up to 25 feet each, giving you multi-room coverage. Place them on solid surfaces or attach to walls, doors and window frames using the adhesive backing. Because the ultrasonic sound corrects all dogs in barking range, we recommend this product for single-dog homes only and for dogs 6 months or older. We have a “No Bark Guarantee.” If this product is not meeting your needs, please contact PetSafe® so we can help you find a different solution for your dog. PetSafe® brand is here to help you and your pet live happy together™.