CU81xx series devices are a combination of intelligent power supply and power storage for safe shutdown on voltage drops. This dual functionality also determines the design. There is a space-optimized, a performance-optimized and a maintenance-free version with capacitors. The housings can be mounted on the standard C-rail in the control cabinet or as a variant with flange mounting. The frontal accessibility of the battery cells enables a change in the cramped control cabinet with the wiring standing still. Interfaces such as USB 2.0 or UPS-OCT provide status values for diagnostics via PC and make the UPSs configurable.