A UPS contains batteries that provide backup power to your system in the event of a power outage to give you the time to safely save all open files and gracefully shutdown the system or even continue to work until normal power has been restored. Additionally, most UPSs regulate the power that comes from the original supply (i.e. the wall outlet). These functions offer several advantages.

Business operations don't stop because the power fails. Equipment isn't damaged due to the stress of another hard start-up cycle.

Valuable data isn't lost due to a user forgetting to save the file or if data had not been flushed from cache.

The UPS eliminates sags, surges, spikes, noise, and other electrical interference that can damage equipment and data or interrupt operations.

The UPS provides a "clean" source of power, eliminating noise that can cause interruptions in operations or data loss.

Desktop computers, network file servers, telephone systems and other critical business equipment play a vital role in the day to day operations of most businesses and the reliable functioning of those systems depend on a clean uninterrupted supply of power.

In many cases, an uninterruptible power supply can be justified with simple arithmetic. Several hours of professional work can be lost due to a momentary brownout. This can crash a computer before the work can be saved to disk. Consequently, an organization can suffer expensive setbacks in terms of time and disruption. But, with an uninterruptible power supply in place, a brownout can pass unnoticed. Spending as little as a hundred dollars on power protection can buy complete protection and peace of mind.