SENTINEL PRO is an on-line double-conversion (Voltage and Frequency Independent) UPS offering high levels of reliability and protection for critical servers, voice and data systems. Each Sentinel Pro has a built-in mimic panel with an LCD to show input and output voltages, and battery charge status. Optional batery extension packs can be added to increase UPS runtime. Each SENTINEL PRO has a USB communication port as standard, with a built-in expansion slot for additional adapters, protocol converters and related contact cards. For longer runtime applications, refer to the Sentinel Pro ER models. Model numbers include SEP700 (700VA) SEP1000 (1000VA), SEP1500 (1500VA), SEP2200 (2200VA), SEP3000 (3000VA)