Duralex has been a specialist in the design and production of tempered glass tableware since 1945. More than ever, it is synonymous with toughness, design, and everyday practicality. These Lys stacking bowls are perfect for a multitude of tasks for cooking and putting ingredients in. Non-porous & doesn't absorb flavors, colors, or liquids. These bowls are extremely strong and are tempered by heating them to 700 degrees. Stackable is so easy to store. If the glass does break then it is designed to break into blunt fragments, much like a car windscreen. Dishwasher and microwave safe, shock and chip resistant.