S4K2U-D and S4K2U-5D Industrial On-Line UPSs are single phase, online (double conversion) UPS available in 1000-3000VA, 120V and 230V. The rugged external contruction includes a steel casing bezel and optional hardwire output terminals suitable for industrial applications. Online design means zero transfer time from external to internal power, so when utility power fails, your critical load remains supported by a seamless flow of power. Housed in a slim 2U package, the rack or tower configurable S4K2UD offers a higher power factor, longer battery life, higher reliability and reduced cost of ownership.