Never used. Still in box. Individually mouth-blown from heat-resistant borosilicate glass, these double wall glasses have a thermal quality that keeps hot drinks hot and cold drinks cold. There’s a silicone vent at the base of the glass that equalizes the air pressure between the two glass layers when hot or cold liquids are added. Dishwasher, microwave and oven safe (up to 356ºF/180ºC). Dimensions: 3.5" dia x 6" h Capacity: 15 oz