Sand the Calluses Away [SEP] Great product. The individual who does my pedicures has a similar product so I had a pretty good idea on how to use it.  I think I would prefer the kind where I could attach sand paper discs. Time will tell how well the permanent disc will hold up.  I suppose I can always still put a sandpaper disc on the unit. Just be sure to not apply too much pressure or the unit will stop turning. Works better than any manual method.