Duralex - Lys Stackable Clear Bowl 12 cm (4 3-4 in) Set Of 6 Duralex is 2.5 times more resistant to breakage and chipping than normal glass, Can also withstand sudden thermal shock, from -4 F to 212 F Duralex glass is very hygienic, It is non-porous and does not absorb liquids, colors or flavors Dishwasher, refrigerator, and microwave safe. products maintain the original look for years