Duralex glass products are tempered. The mechanical and thermal resisting properties are considerably increased to other ordinary glassware products. Prisme Tumblers by Duralex are the perfect weight, functional yet stylish feels extremely comfortable in the hand. Because they are equally suitable for cold and hot food, they can go straight from the refrigerator to the microwave. They are conveniently stackable, impact and chip resistant, microwave and dishwasher safe. With the help of continuous investments and commitment to quality, Duralex has reached a level of excellence that makes its products recognized throughout the world. Duralex is and will always remain a true French manufacturer of glassware and tabletop products, and is the only manufacturer who makes 100% of their products in France.