Duralex - Lys Stackable Clear Mug 250 ml (8 3/4 oz) Set Of 6 Set includes six Clear Mug, Height 6,9 cm - 2 3/4" Diameter 7,7 cm - 3" Duralex is 2-1/2 times more resistant to breakage and chipping than normal glass, can withstand sudden thermal shock. Can also withstand sudden thermal shock, from -4f to 212f Dishwasher, refrigerator and microwave safe, Products maintain the original look for years Dualex glass is very hygienic, It is non-porous and does not absorb liquids, colors or flavors