Take control of training your dog using ultrasonic tone. The Collarless Ultrasonic Remote Trainer emits a sound that is beyond the hearing of most humans, but is audible to dogs. This trainer can be used two ways. First, you can activate the ultrasonic tone to correct your dog's bad behaviors (using the "N" button) so he will quickly associate negative actions with the annoying sound. Second, similar to clicker training, you can also activate an audible beep to reward your dog's good behaviors (using the "P" button). Your pet deserves the best. Trust PetSafe to help keep your pet healthy, safe and happy.