It works much like the battery in a laptop or cell phone when you disconnect it from power. When a UPS unit loses power, it switches to the battery in the UPS to power what is plugged into the outlets that are connected to the battery. You heard that correctly. With this UPS and most others, not all the outlets will provide battery power, but which ones do and don't are clearly marked.

Another way UPS units differ is that many come with computer software and a way to connect a computer to switch the computer off if you lose power so you can have your computer properly shut down. You don't have to use this if you don't want to; it really depends on what you do with your computer for as to whether you need to use this feature. Most modern computers aren't as affected by sudden power loss as they once were. However, if you lose power a lot, you may still want to use this feature.

Of course, you don't have to use this with a computer at all. You can plug in anything you want to have power for a limited time: network, TV, radio, lights, cell phone, etc. You probably won't get much longer use of the battery than quote by the company, but it can be useful for short term power like giving your cell phone a little extra power or a little light to get ready for bed.

The use of a UPS is limited to what you plug into it and the load you plug into it. I would limit what you plug into it to common household appliances like those mentioned above. High load appliances such as refrigerators, AC units, heaters, etc. could cause disastrous problems, so you shouldn't plug these things into a UPS or even a common power strip.