Use UPS Backup System with AVR to guard against surges, spikes, sags, brownouts. AVR steps up low voltages to safe output levels. System has eight outlets (four adapter-sized) and a 6' cord. Included software automatically saves and closes open files and then safely shuts down the computer. Backup system also features 100V-140V input voltage on utility; 120/V+/-5 percent; 60Hz output frequency on battery: 890 Joule rating; 550VA Rating; 330 watts and 1 RJ11 input/2 output. Battery runs up to 60 minutes. To pick the correct UPS system, total the watt requirements of your equipment and add 30 percent extra capacity to ensure the battery backup will function. If your equipment does not give a wattage rating, simply multiply amps x volts to get your watt requirement. UPS systems are not designed for printers, fax machines, heaters or fans.