These award-winning tumblers aren’t just a pretty face; they’re really clever too! Individually mouth-blown from heat-resistant borosilicate glass, our large 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 equalises the air pressure between the two glass layers when hot or cold liquids are added. That means no more burnt fingers from picking up a hot cup of coffee, and no messy condensation so no need for coasters. Lightweight and comfortable to hold, these trusty tumblers offer countless serving possibilities, from coffee, tea and hot chocolate to cold brew, soda and cocktails. So you only need to buy one type of glass for your home! Innovative double wall construction that keeps hot drinks hot and cold drinks cold. Also perfect for serving soup or cold desserts. Made of mouth-blown, heat-resistant borosilicate glass. Hydrophobic silicone vent that equalises the air pressure between the two layers of glass. Dishwasher, microwave and oven safe (up to 356oF/180oC). Style number: 4560-10