The Z1 has an integrated battery system called the PowerShell. This system delivers a full night of cord-free power on a fully-charged battery.
The PowerShell unifies a 45 Wh battery module with the Z1 to create a platform that delivers at least 8 hours of cordless cpap. It is a great solution for travelers, outdoorsmen/women, or as a standby power-solution that automatically powers the Z1 when the power goes out.