Lys 6 piece set includes 6.75 inch stackable clear bowls;The original french tumbler, made by the company that invented tempered glass;Duralex is 2-1/2 times more resistant to breakage, sudden thermal shock and chipping than normal glass;Duralex glass is very hygienic: it is non-porous and does not absorb liquids, colors or flavors;Dishwasher, fridge and microwave safe; products maintain the original look for years