The DIGITUS USV Battery Modules ensure that USV systems used in highly demanding environments can continue to reliably supply connected devices with power in case of interruptions to the power supply. A maximum of 4 battery modules can be connected in order to increase the operating time of the connected IT devices. The systems are protected by ensuring uninterrupted power supply while changing the batteries. The external battery backs can ensure a rapid increase for the bridging period in case of increasing need.