Set of two, 4oz. elegant double-walled espresso mugs. Made from hand-blown, chemistry-grade borosilicate glass. Double walled-design insulates the glass, keeps your favorite espresso shot warm longer, and creates a dramatic optical illusion, so your coffee looks like it's floating in air inside the mug, while the outer glass remains safe to touch. It also prevents condensation and creates a rounded rim for comfortable drinking. A design that is practical and visually appealing makes this an exciting product for any home or special gift. The durable, hand-blown glass allows it to be made thin and light while still being durable. And, it has far fewer defects, if any, compared to other glass mugs Dishwasher safe; microwave safe; freezer safe. Not recommended for use with metal utensils. All Eparé products are backed by the Eparé Limited Lifetime Warranty.