Pretty great mouse, I upgraded from the normal 502. Kind of pushing my foot forward in the shoe - maybe this is something unique to me as I am pigeon-toed (?)Sizing is spot on, I ordered a 9 and the fit is literally perfect. La parte rígida de la suela me pegaba justo en el talón y es muy incómodo. Initially I was nervous when I read the instructions as they did not provide very much detail and I did not realize that there would be so few steps. Is worth the purchase. Its too early to give excellent credit but 4 stars is more than enough for now. Slippers are great. It holds me in & made me sweat right away. The problem is when you go to tighten it, the screw goes past the end point and becomes loose again. And guess what? Problem solved!