A Sam’s Club Exclusive - Medium Automatic Pet Door Value Kit includes an Automatic Smarty Pets Door complete with U4 Collar, rechargeable back-up battery and wall adapter tunnel, which allows easy, quick, and professional looking wall installation. Engineered for performance, design, value and extreme reliability, Smarty Pets electronic pet doors are fully automatic and activated by a tiny ultrasonic collar. They feature a translucent door panel made of a new super-strength, bulletproof resin. When your pet approaches, the air-tight panel quickly and quietly powers upward. Because the panel moves up and down and does not swing out, it is mounted in air-tight vertical grooves. This mounting arrangement makes it impossible for an intruder to kick it out. The result is a pet door that is easy to use for your pet and very secure against intruders and stray animals. Automatic Smarty Pets doors are completely wind and weather-proof with zero draft even in strong winds For cats and dogs up to 30-pounds Operates on AC adapter (included), or rechargeable backup battery (included), which snaps into the battery compartment to keep your automatic Smarty Pets door functioning in the case of a power outage Optional battery charger (sold separately) to operate your automatic pet door without AC wall connection