Genuine High Tech Pet Brand, Reliable MS-5 Transmitter Collar, From the Makers of Your Power Pet Door 100% Waterproof Specifically Designed to Work With Your Power Pet Door's 4-Way Access System No False Triggers, Reliable Operation Opens the Power Pet Door Every Time Proprietary Silent Directional Signal Opens the Door Only When Your Pet is on a Direct Approach to the Door The Signal Cannot be Heard by Your Pet Long Battery Life (3 - 4) Months One Size only, fits most dogs and cats Don't trust your pet to anything less than a geniune High Tech Pet brand Pet Door collar No Other Brand Has the Proven Reliability of a Genuine High Tech Pet Brand Automatic Pet Door Collar Genuine High Tech Brand from the Makers of Your Power Pet door. The one and only MS-5 ultrasonic collar is a premium quality unit that operates all High Tech Pet Power Pet electronic pet doors. Using all digital circuitry, this provides the true digitally coded signal your Power Pet door needs to open reliability every time. Includes a specially designed B3V1A battery which lasts 3 – 4 months and prevents damage to the circuitry if the battery is accidentally installed incorrectly. 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 immersible to a depth of 3 meters 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. Small and lightweight, one size fits all dogs and cats. Comes with an attractive and tough 27 inch nylon strap and Includes 2 FREE Batteries!