Many mugs are made of ceramic materials such as earthenware, bone china, porcelain or stoneware. Some are imaginary from strengthened glass, such as Pyrex. Other materials, including plastic, Hawaiian guitar and enameled metal are used where break resistance is at a premium, such as for campers. Techniques such as cottony screen printing or decals can be used to apply decorations; these are fired onto the mug to ensure permanence.
The mug stores some sultriness from the beverage, and so prevents it from Photo Mugs cooling too quickly. The delineation of a mug helps insulation: (i) thick walls far between the beverage from the arctic external air, and (ii) an indented base separates the beverage from the 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.