APC Back-UPS ES 550 Surge Protector 8 Outlet 550VA With battery. Works Great.The APC Back-UPS ES 8 Outlet 550VA 120V provides surge protection through eight outlets, regardless of whether the UPS unit is turned on or off, and battery backup through four outlets when turned on. Connecting a single-line fax machine, modem, or telephone to the data line output will also protect these communication devices from a power surge. For maximum performance, charge the UPS unit for a minimum of 16 hours. The output power capacity and configurable power for the APC Back-UPS ES 8 Outlet 550VA 120V is 330 watts. The nominal output voltage is 120 volts. APC includes a PowerChute Personal Edition software CD as part of the accessories. In case of a long-term power emergency, this software can automatically save files and shut down the computer’s operating system.