The SENTINEL PRO has evolved from the highly successful Dialog UPS series. The UPS has a unique, modern design and improved electrical characteristics, representing a benchmark product from the Riello UPS research and development team. SENTINEL PRO uses On-line double conversion technology, resulting in the highest levels of reliability and maximum protection for critical loads such as servers, and IT and Voice/Data applications. For business continuity applications requiring long battery runtimes, runtimes up to several hours are possible, using ER models fitted with more powerful battery chargers, and battery extension packs. The front mimic panel has been entirely redesigned, adding an LCD display that shows the input and output voltages, and battery readings in addition to UPS operating status information. The inverter and the microprocessor control stage has been completely redesigned to provide increased efficiency and greater configuration options.