High Tech Pet Ultrasonic Water Resistant Power Pet Doors Replacement Collar Operates all High Tech Pet Power Pet electronic pet doors and 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 With a fully enclosed ultrasonic speaker, the MS-4 is water-resistant and rugged Immersible in water for short periods of time; stands up to heavy rain showers and is perfect for dogs who love to play in the snow One size fits all dogs and cats; includes an attractive, tough 27 inch nylon strap