Does this power saver box really work?

I saw this at the mall lately and they claimed it could save you 30 percent off your electric bill. Since my air conditioner is the biggest part of my electric bill and the most expensive, if it really worked I could save a lot of money as it's so hot here that I have to leave it on all the time.
But this thing sounds too good to be true. Does anyone know if it really works?
Here is a picture and description of the product.
http://www.yugatech.com/blog/toys-gadge ... ng-device/
But this thing sounds too good to be true. Does anyone know if it really works?
Here is a picture and description of the product.
http://www.yugatech.com/blog/toys-gadge ... ng-device/