These are wonderful slippers.  I bought them for my daughter and she loves them.  They do run small though.  She wears a size 12 shoe and I ordered the M (13-1) size.  She foot fits in but her toes are scrunched.  I didn't return them to get more...because she wouldn't let me get them off her feet. :) I'm sure we will be ordering some in a bigger size soon.