For your next adventure, pack up the geckobrands Hydroner 20L Waterproof Backpack. Because it's waterproof, it's perfect for sailing, kayaking, camping and more. It even has a special sleeve that allows you to see and use your phone, while keeping it safe and dry. With a 20-liter capacity, this bag can hold towels, snacks and everything else you might need for a day in the sun. Padded shoulder straps.