I have terrible feet and I get big calluses on the side of my big toe and my heels get thick and rough. This is the only thing that takes it away. You just rub it back and forth across the rough parts with moderate pressure and be careful to stop before you file away too much. The ped egg holds the shavings inside it and when you are done you can open it and see all the powdery skin inside! It usually soak my feet before using it and it only takes a few minutes. The blades are replacable but I've never had to replace mine and I've had it a few years. I definitely recommend this to people who have bad spots on their feet.