This set of large, medium, and small food storage containers makes it super easy to pair the right lids and containers using the Color Mates matching system -- simply match the color of each lid seal to the corresponding color dot on the bottom of its matching container. LocknLock's unique 4-hinge locking system has been durability tested to last up to 3 million uses, and the enhanced silicone seals are 100% airtight to keep foods fresh longer and 100% leakproof to prevent messy drips and sloppy spills.