This waterproof digital ultrasonic collar operates all High Tech Pet Power Pet electronic pet doors as well as Sound Barrier and Yard Barrier sonic fences. Using all digital circuitry, this state of the art design provides a stronger signal and maintains better accuracy over all temperature ranges. It includes a specially designed B3V1A battery which lasts about 3 months and prevents damage to the circuitry if the battery is accidentally installed incorrectly. With a fully enclosed ultrasonic speaker, the MS-5 is waterproof and rugged. It’s perfect for the pet who likes to do some serious “ruff housing”. The MS-5 is fully immiscible and will continue to work when wet. It will stand up to heavy rain showers and is perfect for dogs who love to play in the snow. The enclosed transducer (speaker) is much more robust than conventional open air transducers and will stand up to far more abuse from your pet. Small and lightweight, one size fits all dogs and cats. Comes with an attractive and tough 27 inch nylon strap.