OPTI-UPS CS730B 730VA Clever Series 3 Year Warranty / Live US Support & Fully digitized microprocessor control Energy saving (UPS sleep mode ) & 50/60Hz frequency auto sensing Buzzer can be muted by pressing "ON/OFF" button & Advanced battery management (ABM) Single PCB with reliable design and Clear LED alarms and Surge protection of all outlets & EMI/RFI noise filter Cold start (DC power on) & Short circuit and overload protection & Automatic diagnostics & battery check