Multiple use Vacuum Flask to Store Hot or Cold Beverages. The Haers Vacuum flip lid flask has a stainless steel body 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. Made of 100% Stainless Steel: The body of the Vacuum flask is made in 18/8 quality stainless steel.