I bought this in green in a size medium for my 25 pound pug. He fits perfect in it and absolutely LOVES it! There is room to roll up in a ball and stretch out. I like that it is completely enclosed because he likes to use the sides as a pillow.  My only complaint is that it is not a covered dog bed and no piece is detachable, so you have to wash the entire thing. I've washed it many times and air dry it, and the color has only faded a little (but it's a tight squeeze in my smaller size washer).