http://www.refurbups.com-- APC's Smart-UPS line is one of many that does do a pure sine wave output.

The electrical supply might be inconsistent in your area. But blackouts can’t keep you from going about your day and getting things done, can they? When the electricity goes out in your area, a pure ...

If you’re serious about protecting your PC—and any unsaved work or game you might have open on it—you need an uninterruptible power supply (UPS). A UPS is a surge protector and emergency battery in ...