I bought this file at Sephora. I have bought many callous removing files, graters, stones, etc. All of these products either dull quickly or are too time consuming. This product recommends that you use it on dry skin. The file is slightly flexible. It removed my heel calluses well with not a lot of work. It leaves your heels smooth with no roughness. I have read that this file lasts a long time. I would hope so since the price was 38.00. I think it works great.