The first thing you notice about the XantrexXPower PowerSource 400 is its heft. This fairly compact backup device promises up to eight hours of power to keep a basic office setup running even when the outlets go out. That generous amount of time is where it differs from an uninterruptible power supply--most UPS devices are there to help you through power sags and spikes, and then give you less than an hour to save your data and shut down your equipment.
We took the PowerSource 400 for a test drive. You get surge protection and five outlets, all of which connect to the battery backup. We plugged a 15-inch LCD monitor, a laptop and a 40-watt lamp into the fully charged PowerSource and then pulled the main plug. With that load, the PowerSource 400 supplied about five hours of working time. That's more than enough to get you through most power outage incidents or to wrap up pressing business needs during a major interruption. Bear in mind that power-hungry devices like high-wattage lamps, CRT monitors and laser printers can cut into your backup time. At $199 (street), it's a small price to pay to keep your business up and running.