The PetSafe Ultrasonic Remote Trainer is a training system that takes advantage of your pet's sensitive hearing with a sound that is beyond the range of humans. When the system emits its ultrasonic sound, your furry friend will understand that you want him to stop whatever he is doing. The system features a positive tone to reward good behaviors as well as a negative tone to counter undesirable ones. With a range of up to 30 feet, it is suitable for use on dogs of any size. The remote uses one 9-Volt alkaline battery which is included.