Long heat and cold retention. Sufira's vacuum insulation technology locks in temperature to preserve flavor and freshness, that keeps beverages hot for 12 hours or cold for 24 hours. Our double walled thermal flask is made up of a durable metal interior and exterior, built to withstand the demands of everyday use. Its large mouth opening makes filling and cleaning easy; it can even be used with ice for extra cold refreshment. Its outer body stays cool to the touch when filled with hot liquids and is condensation-free with cold beverages. Original design. The intricate design and colors reflect the European influences and is reminiscent of a romantic era.