Made of durable, heat resistant, mouth-blown borosilicate glass of the finest quality, the 12 oz. Serafino glasses are the largest in the Ozeri Artisan Series of award-winning handcrafted drink ware. Borosilicate glass is stronger than common glass, shatter-resistant and with the Serafino"s double-walled design, it offers the ultimate insulation to maintain drinks at their ideal temperature. The Serafino"s unique double wall design suspends drinks within an inner wall for an attention-grabbing optical effect, while the wraparound contour provides a natural aesthetic grip. Each glass is made to keep your hands cool even with your hottest drinks and free of condensation with your chilled beverages. The patent-pending Serafino is great for coffee, cappuccinos, hot or iced teas, cocktails, frozen beverages and much more. Each set contains 4 handmade glasses designed for lifetime use. The Serafino glasses are completely dishwasher, microwave and freezer safe and ship in an elegantly printed and carefully packaged box with a 1 year warranty.