Anchor Hocking designed the TrueSeal Glass Food Storage products to prevent spills and leaks by utilizing the BPA-free, textured lid, which seamlessly forms to the glass container. The airtight seal ensures that transporting and keeping food fresh has never been safer or easier. Number of Pieces: 16 Set Contains: (2) Round 1 Cup, (2) Round 2 Cups, (2) Round 4 Cups, (1) Rectangular 4-3/4 Cups, (1) Rectangular 6 Cups Glass Food Storage Containers with Mineral Blue TrueSeal Lids Glass: Tempered Tough Glass Seal: Air Tight Food Seal Use: Freezer, Microwave, Oven, and Dishwasher Safe