Regarding the size I advise to look at the table. I use a 43 and ordered the 43 and perfect. Aesthetically they are nice and the slippers have a good finish and a good presence. The closure works smooth and seems robust but, at least in my case, they are not for MTB. The foot slips over the aluminum pedal, has no grip. And that I haven't done any descent, just a small road on the beach. The gray part of the sole is excessively hard, resembles a flexible plastic. You're pedaling and continually you have to put your foot on the pedal. When you're going to start the march you have to be careful to force because you can slip and hurt yourself with the pedal. The Black part is even harder but it doesn't matter because it has no contact with the pedal