I used the guide comparing the tip of the heel to the size of a dime and it is very misleading. The Large was way too big for the heel I needed to repair. I tried to use the caps on another pair to put them to use but when you put them on, the plastic cap looks cheap and the adhesive strap that secures it looks a lot like electrical tape around the bottom of the heel. These would be fine for a quick fix in a pinch (be careful of sizing) but for me they would not be good enough for long term use. With this product you get what you pay for.