These shoes are great. I love them they are great for bouldering and sport climbing. These shoes do stretch A LOT. Most people say that you should go one size down, but since it is a slipper I went smaller because they will have the tendency to slide on your foot on the occasional heal hook. I normally wear a 43.5 but I went to a 41 and have had no problem on heal hooks. I have a very narrow foot, and they fit great. I have kinda hairy feet, so when I put on the shoe it will tug on the hair making it some what uncomfortable so I just have to shave my feet periodically. This is very well worth the money. La sportiva will resole your shoes for you.