Made in France since 1939. Impact & chip resistant, extremely durable Duralex tempered glass is 2.5 times stronger than ordinary glass. Shock resistant manufactured to withstand sudden temperature extremes from -20 C to 130 C and is suitable for hot or cold liquids. Stackable. Duralex glasses and bowls are stackable for convenient and space saving storage. Hygienic nonporous Duralex glass does not absorb liquid. Freezer, microwave & dishwasher safe. Adaptable modern glassware can go directly from the freezer to the microwave.