I bought this from the Sanrio website! I fell in love with this bag, a collaboration between the picture book "The Very Hungry Caterpillar" and Hello Kitty, and bought it! The inside is nylon fabric. The outside is a thick fabric, but I don't know what it's called (the kind of fabric you often see on bags). I bought it for my child, but it was hardly used outside. It's cute for children to carry, but it's also recommended for parents to put in things like baby bottles and diapers! I think I bought it over 5 years ago. - Although it wasn't used often, there are some areas with slight stains and some pilling in places (see photo 5). - Please check the size in photos 6-8. This item has been used by a child. Please refrain from purchasing if you are sensitive to these issues. Thank you!