"I love these things. They are so warm. Some other reviews elsewhere say that if you are a 9.5 or bigger, buy a size L -- not true -- I am a size 10, I bought a medium, they were a bit too tight for the first night or so I wore them, but they fit perfectly now. Because they're all fabric, they will kind of mold to your feet.They are super warm, comfy and great as slippers. I live in upstate New York, it is freezing here, all the time, and these are perfect for walking around when I get home from work. They don't come off until I crawl into bed each night."