The CyberPower Supply offers back-up battery & surge protection for the FreezeAlarms, HomeSitters, TempAlarms or any other plug-in devices. The battery back-up keeps devices running in case of a power outage. Once the power is restored, the rechargeable battery will be recharged. The CyberPower Supply also offers surge and data line protection against sudden power surges or spikes. CLOSEOUT ITEM!!! All sales on this item are final.