Good product, but came with no instructions on how to use or change the blade.  It's not that simple to figure it out either.
Product came with no instructions on how to use or replace the blades.  I had to go to YouTube to get instructions.  My callous is on a spot of my foot where the skin is thick, so I didn't have the problem that some users had with the blade going to deep, but this is not a flaw in the product.  You can shave off as little skin as you want.  Just imagine peeling an Apple with a knife.  You control how deep you go, so this is a user problem and not the fault of the product.  Once I figured out how to use the product to include changing out the blade, this product is a life saver.  Just wished that it came with some kind of instructions.  If I did come with instructions I would happily had given it 5 stars.
Rating: 3 stars