basically you slot a little eraser in the end, press a button and it spins round really fast. you can erase it to a point and use it to create sharp edges or erase really small areas.
it's the first time I hear about it. It's exactly what I need!!! But I know we don't have them in here. We don't even have eraser pencils. I had to order from eBay. I will see if they sell this on eBay as well. Thank you very much