External charger kit with backup battery for your Power Pet electronic pet door. Includes charger base, AC adapter and two rechargeable B12V-1.3 backup batteries. Allows you to operate your Power Pet Door in battery-only mode, eliminating the need for an AC wall connection. For battery-only operation, use one battery in your Power Pet door and keep the other in the charger base. When your pet door battery runs low, just swap. Battery change takes less than 30-seconds.