The DC-DC Uninterruptible Power Supply (UPS) has been specifically designed for use with the Protectli Vault. It can be used to provide DC power to the Vault in the event of AC power loss to the Protectli DC power adapter. This UPS is rated at 44 Watt Hours. That means it can supply DC power for a total of 44 (Watts * Hours). For example, if the Vault uses 8W, it can supply power for 5.5 hours. The UPS unit ships with a DC-DC power cable to connect the output of the UPS to the DC input of the Vault and brackets for optional wall mounting.