I own a couple of these devices.
I bought them from Provantage
the CyberPower AVR ones are great.... and great "bang for the buck"
http://www.provantage.com/avr-series-ups~22070022.htm
... batery backup, voltage regulation (keeps the voltage in a safe range) and surge protection.
I just bought a 1500 AVR - for about $150 delivered......