The ultimate container has a smart lid colour match system where lids and bases match in colour, any lid matches any red base – its so simple and smart! The Realseal™ lids have have a soft seal that makes the storers airtight and leakproof. The lid also has an air release vent, which allows the storers to be used in the microwave for reheating. All the storers are clearly marked with coloured graduated measurements. They nest inside each other to save space and are modular by colour. 6 lids fit 24 bases over both plastic and glass storers. All Décor containers are BPA Free, Microwave safe, Freezer & Fridge safe & Dishwasher Safe