I ordered two pairs of Crocs - one pair of thongs and one pair of cayman crocs. I used the sizing chart provided and ordered both pairs in M5/W7. However, when they arrived, while the Thongs fit perfectly, with room to wiggle, the Caymans were way too small (I'd almost say a full size too small). The Thongs were "made in China" and the Caymans "made in Mexico". I went to my local store and discovered that they receive Croc orders which are often made in multiple countries. It would appear to me that there is no "standard" mold used. So beware - just because you have tried them on in a store and think you have the correct size - you may end up getting a larger or smaller size, depending on where they are manufactured.