The new Onyx Glass and Stainless Steel Airtight Container is made from 18/8 stainless steel, FDA approved silicone, and borosilicate glass. Dishwasher, oven and microwave safe. ( **Lids NOT microwave safe**) These containers are perfect for leftovers, for the freezer or for on the road. Just push the silicone button down to create an airtight seal. Pull the button up to release the seal, and lift the lid.