I was already a fan of Haflinger slippers when I purchased these.  As a cat lover, I was afraid that cat slippers would be too over-the-top.  Oh, but you know what?!  You can wear whatever you want at home!  Give into the wool goodness!  Kitties!!!  I went against Haflinger suggestion and got a 39 for these (I consistently wear a 39) and I LOVE THEM.