• The mug stores some calidity from the beverage, and so prevents it from cooling too quickly

• The form of a mug helps insulation: (i) thick walls apart the beverage from the cool external air, and (ii) an indented indelicate separates the beverage from the Photo Mugs surface upon which the mug is set
• The shape of the base forms the characteristic O-shaped stain, so often seen upon desks and documents.

A travel mug is a variation on the traditional mug that is finer for transporting hot liquids. It may or may not be a vacuum flask, but is customarily well insulated and completely enclosed, with an easily closed opening on the top.