This 18-piece glass food storage container set includes 9 glass containers and 9 matching locking lids. It comes in various shapes and sizes: rectangles (large 35.5 oz. medium 21.6oz, small 12.5oz), squares (large 27 oz. medium 17.6 oz. small 10.8 oz.), and rounds (large 32 oz. medium 22 oz. small 12.5 oz.). Closing the lids is effortless: you don't need to hold the container by hand or leave the table; just use 5 fingers to seal them tightly. The lids have high compatibility with the high-borosilicate glass, making them not only easy to close but also highly airtight. These containers are safe for use in the oven, microwave, freezer, and dishwasher. They can withstand temperatures from -40℃/-40℉ in the freezer up to 400℃/752℉ in the oven. However, note that the lids are not safe for ovens or microwaves, so remove them before heating or cooking. While the lids are dishwasher-safe, high temperatures over time might deform the silicone sealing strip, so hand washing lids is recommended. Made from high-borosilicate glass, the containers are BPA-free, durable, and easy to heat. The non-porous glass and BPA-free lids with a special snap-down design ensure they are leak-proof and airtight.