Made from tempered glass, our Glasslock™ Food Storage Containers are manufactured to withstand repetitive use in the refrigerator, freezer and microwave. You can store, heat and serve food all in the same, attractive container! There's no worry about warping, staining or absorbing food odors. The unique snap-lock lid system features a durable silicone seal and is easy to open and close. For compact storage, the graduated sizes can be nested with their lids on.