PetSafe SmartDoor Plus Rechargeable Battery with Charging Station SmartDoor Plus and Passport Pet Doors Works with the PetSafe SmartDoor Plus and Passport Pet Doors for full operation or as a battery back-up in case of a power loss Can be used if there is no power outlet nearby to operate the SmartDoor Plus or Passport Pet Door Rechargeable lithium-ion battery so no need to keep replacing batteries; Charge time is 4 hours or less Typical battery life is 5 to 7 days, depending on if battery is used for full operation Includes 1 rechargeable lithium-ion battery, charging station, power adapter and detailed instructions