The double walled Thermo Glass is built with a vacuum between the two walls in order to keep hot ingredients hot and cold ingredients cold. Not only is your presentation elegant and sophisticated, it is also multifunctional . Product designers and Engineers thought about everything; from tactile experience of the actual glass and form, to location of the logo and safety valve, to the little lip at the rim of the glass that is meant to give a little extra "oomph" to the beverage, dessert or anything else you are serving. Thermo Glass, 8-1/2 oz. (250 ml), 2-1/2" dia. x 4-1/4"H, double walled, high-temperature, shock resistant, dishwasher/microwave safe, tempered, borosilicate glass, clear.