I am just using a UPS (Uninterruptible Power System) for my desktop pc, but some pc salesmen says that for added protection I have to also use an Automatic Voltage Regulator (AVR) before connecting it to the tower casing power connections. Maybe, they’re just doing some sales talk to have more sales of their products. But at the back of my mind, maybe they’re right. As I already know that the main functions of AVR is to maintain exact amount of power that goes out while UPS main role was just for back-up power when there’s power failure so as not to interrupt the power supply of the pc. Two is better than one… possibly. But I would like to ask you people what are you using?