S4K4U-C 6 kVA and S4K6U-C 10 kVA Industrial On-Line UPSs are the first true online industrial uninterruptible power systems that provide flexible output voltage, an integrated maintenance bypass switch and internal batteries all in a slim 4U (7.0") or 6U (10.5") enclosure. They feature double conversion topology to provide the ultimate in protection against a wide range of potential power problems.