The Co-Pilot 12 can be permanently connected with the Pilot 12 CPAP battery and your PAP device. As soon as the main power goes out on the Pilot 12 battery, your PAP device will begin running of the Co-Pilot 12. If your PAP device is used with a heated humidifier, the life span of your battery will only last 3 to 4 hours. With the added Co-Pilot 12 you will be able to sleep through the night without being disturbed by an extended power outage.