In the US, Canada, UK and Australia, it's likely marketed as AVS, or automatic voltage stabilizer. Mainly used in areas that have questionable power grids or poor wiring with a lot of fluctuation in homes or businesses. If any of those things apply to you, it couldn't be a BAD idea, but the decision should be based on those criteria since your power supply itself doesn't necessarily require one. A good idea is a power conditioner WITH AVS. If you're power grid is fairly reliable and the wiring in the building where your system is located, then you probably don't need one. If it's not, it might be a good idea. If you get a lot of lightbulb and appliance power fluctuations, I'd at least consider adding one.