1.Borosilicate Glass 2.[12 Pack glass storage containers] Set includes 12 Square containers with 12 Airtight Locking Lids, for a total of 24 pieces. Lids are interchangeable between the same size glass containers 3.[Oven, Microwave, Freezer Safe] borosilicate glass containers designed to go from zer to oven, containers are great for meal prep, leftovers, cabinet storage, and more, make meal prep simple and easy. 4.[Dishwasher Safe, Easy to Clean] Glass containers won't absorb stains or smells, Containers and Removable silicone seals are dishwasher , making cleaning them a breeze. (please note Plastic lids are Top-Rack Dishwasher Safe.) 5.[Airtight Lids, Easy to Store]: Four locking tabs creates an airtight seal for food freshness, enables the lid to flip open and shut quickly, These lids will not break or slowly stop working. Containers and lids are stackable, and your cabinets stay organized 6.[Leak-proof, Multipurpose Containers] leak-proof and airtight seal, making these containers perfect for taking meals on the go; great for taking lunch to work and ideal for meal prep at home and perfect for the gym, pool, or work.