I've only used this once when I went to Disney. I wanted a loose fit, so I chose a size L. I'm slender myself, but it was just right for the loose fit I wanted. The children's size is 150. Please confirm any unclear points beforehand. It will be folded up small and shipped in simple packaging. It will likely wrinkle. Please purchase only if you understand this. If it fits in an envelope, it may be sent in an envelope.