The airtight lids of these containers preserve freshness. They're sized just right to prevent the contents from sliding around and getting crushed. Set includes a round container with lid (4-3/4"W x 2-1/2"D x 4-3/4"H) and a rectangular container with lid (5-1/4"W x 3"D x 5-5/8"H). Polypropylene. Dishwasher, microwave and freezer safe.