Liebert PSI is a feature-rich UPS system with industry leading 0.9 power factor. Its high power output delivers superior performance on power factor corrected (PFC) power supply and satisfactory backup time in the high demand environment. Liebert Multilink UPS software protects servers through local USB communication or via a network. Matching external battery cabinets offer UPS backup time to several hours in the extended requirements (for Liebert PSI-XR models only).