Size is M. I'm selling this because my child has outgrown it. I think it's a good size for children around 150cm tall. Worn once last year. I don't see any noticeable stains, but please refrain from purchasing if you are concerned about the slight fuzziness of the fabric on the seat, as shown in the 8th photo. Please only purchase if you understand that this is a used item and has been home-cleaned.