They say 2T but they dont fit my 21 month old. Id highly recommend! I Think this could be a good rack pannier but it seems too fragile to the elements. My only issue is that the zipper pull will make noise as you move around (clackin against the zipper. I am trying to get my gear in order (slowly) and after many hours of watching and reading reviewer content I decided on this one for $64. They are warm - perfect for winter to keep my feet warm. I have a specialized pitch with 27. Well, it does a very poor job of that making the gauge almost useless. )Also you can change between three EQ modes: Bass, Treble, and Normal by pressing the play button and (+) at the same time.