The Milton Thermosteel duo deluxe flask has a stainless steel body with copper coating for better heat retention. The vacuum insulation helps in keeping liquids hot or cold for up to 24 hours. This design is extremely sturdy and useful for storing hot and cold beverages like water, coffee, tea, juice and much more. Additionally, it comes with a unique flip lid that makes it easier to drink directly from the flask or to pour into cups and glasses without spilling. Whether you are at work, home or travelling, the Milton Thermosteel flask will come in handy.