The set contains six 12-ounce glasses. These Picardie tempered glasses are stackable and appropriate for both hot and cold beverages. They are the original French tumbler, created by the company that pioneered tempered glass. Duralex is 2-1/2 times more resistant to breakage and chipping than regular glass and can withstand sudden thermal shock from -4-degree F to 212-degree F. Duralex glass is highly sanitary, as it is non-porous and does not absorb liquids, colors, or flavors. These products are safe for use in the dishwasher, fridge, and microwave, and they will maintain their original appearance for years.