I purchased the XS size for my 4 year old daughter (35 lbs, 40" tall).  It fit her very well.  This size may be a little snug on a taller child.  I was able to put leggings and a heavy jacket underneath for trick or treating.  The fabric is a super soft and comfy plush velour and the headpiece was also comfortable for her.  The wings have flexible wire in them so you can stand them up.  The only negative about this costume was that the inner layer was a mesh-type fabric, and the back velcro closure easily snags on it when trying to get it on and off.  Its not a big deal since it doesn't show at all.  My daughter got a ton of compliments on this costume - she was the only owl at her preschool party!  I was frequently asked if it was homemade.  Definitely recommend!