The Explorer is our only leakproof lunch box.  The Rover, Shuttle and Launch boxes are designed to keep foods from “touching each other." When you close one of these boxes, the top and bottom meet so that foods will not co-mingle even when the box is carried inside a backpack. The boxes are not designed to be leakproof or air tight. Messy and wet foods like yogurt, dips and applesauce should be packed inside the Big, Little and Tall Dippers.