Now you can operate your Power Pet Door in battery-only mode with the High Tech Pet Products Charger Kit for Power Pet Door. Eliminating the need for the AC wall connection, this external charger kit comes complete with a charger, two rechargeable B12V-1.3 backup batteries, and an AC adapter for the charger. Place one battery in the Power Pet door and keep the other on the charger base. When the pet door battery runs low, simply swap the two. Your already-amazing Power Pet Door just got even better.