The BF-3V custom Bluefang battery provides lasting power to our new Bluefang Smart Phone Controlled Training, Bark Control and Containment Collars. Uses High Tech Pet's patent pending, dual voltage system that supplies 3-Volt to the collar's processor and other low voltage components, while simultaneously providing 6-Volt to the shock transformer and other high voltage circuits. The result is a very efficient power system that stretches battery life to the maximum. This ingenious collar power system is only available from High Tech Pet. Each Bluefang collar requires a single BF-3V battery. In bark control and electronic fence mode, a well-trained dog who has learned to control his barking and challenges the boundary infrequently, will go through a battery about every 2 months. However, during the initial training process when the collar is working hard producing stimuli to train your dog, the battery may last only a few weeks. Likewise, in remote training mode you may find yourself relying on the more intense stimuli during initial training. Once your dog has curbed her bad behavior and responds quickly to the positive tones training will use less battery power. Therefore, we recommend that you start off with the battery included with your Bluefang collar and a couple of spares. After that, figure that you will purchase about 5 or 6 batteries per year depending upon your dog's individual behavior.