This hand-blown borosilicate thermal glass is for hot & cold drinks. It''s the type of glass Pyrex is made from. The double wall keeps the heat in but you can feel the warmth. No coasters & no sweat & colder longer with cold drinks. This type of glass is typical for laboratory glass for its strength and low thermal expansion, a higher fire glass and more robust. This hand made design has a bevel on the top inside of the glass and then straight lines for simplicity.