Our Lightweight Backpack Coolers come in a 15 can capacity. These backpacks have plenty of room to store what you need to keep cold for up to 24 hours. Two mesh side pockets for easy access & storage of water bottles. The top lid has an interior mesh pocket perfect for dry snack bag storage. The outside is made of heavy-duty polyester with an interior utilizing high density insulation. This item is constructed with a fabric zipper, not a waterproof zipper. Lightweight Backpack Coolers may leak liquid contents.