TARWAY Durable Packable Foldable Handy Lightweight Laptop Backpack Waterproof Travel Daypack (black-35L)

Awesome bag... I brought it during the trips to Dewey beach and several national parks.The bag is light, waterproof, comfortable to carry and easy to folds up into small pocket(just Sandwich size). I threw bottle water, swimsuit, lunch, umbrella, iPad and cosmetic bag into the bag and it kept things organized. Can be used for everything from packing that extra bag in the carry-on, to taking it to the supermarket to load up at check out~~