I bought one of these stretchers for my wife's shoes and the product works great for her. We have stretched multiple shoes and they are much more comfortable for her. I wanted to try and widen the front tips of my shoes so I bought the correct size for my shoes of 8.5 - 11 since I wear a size 9. However when the product arrived I could not fit it into any of my size 9 shoes. My guess is that if you are on the edge of the scaling system, you should get the smaller size foot fitter. I did not end up getting the smaller size because I realized that I could use my wife's stretcher to stretch my shoes. The product works great and if you buy the wrong size, at least you can always return the product and get a different size.