The Maison & White Double-walled glass mugs are a practical and stylish way to insulate your hot and cold drinks. The durable construction means the glasses are a practical and perfect part of your everyday tableware. Made from mouth-blown borosilicate glass the mug can withstand very high and low temperatures and the valve at the base of the glass allows for changes in pressure within the glass. The insulating, double wall will keep your hot drinks hot and cold drinks cold for longer than traditional glasses. Enjoy hot drinks without burning your fingers, whilst cold drinks will stay chilled and not create any condensation thanks to the two wall design, eliminating the need for a coaster. Once you've enjoyed your delicious hot beverage, place them in the dishwasher (these mugs have all passed dishwasher safe testing by TUV) for easy and quick cleaning!