Trudeau's double wall cups create a layer of insulation. They are condensation free so need for a coaster. Cool to the touch. Made of double-wall borosilicate glass which is highly resistant to breakage. Ideal for hot or cold beverages, these double-wall coffee glass mugs maintain the temperature of your drinks. The double wall ensures that the mug doesn't get too hot with hot beverages, and prevents condensation for cold beverages. This classic mug set has a handle for extra comfort.