Seems to do fairly good job
Allowed to feet to soak for at least 1/2 hour in warm water with baby oil and small amount of liquid hand soap.  Removes callus area fairly well. Had to use several passes to remove as much callus as I wanted.  Did not seem to remove too much at one time.  I am satisfied with product.  Do wish it had a means to protect razor area with storage.
Rating: 4 stars