What is vacuum flask?

A vacuum flask, also known as a thermos or insulated bottle, is a type of container that is designed to keep liquids hot or cold for an extended period of time.

The main feature of a vacuum flask is its double-walled construction with a vacuum-sealed layer between the walls. This vacuum layer prevents heat transfer through conduction and convection, helping to maintain the temperature of the contents inside the flask.

Vacuum flasks are commonly made of stainless steel, glass or plastic, and come in various sizes and shapes. They are typically used to keep beverages such as coffee, tea, soups, or cold drinks at a desired temperature while on the go, during outdoor activities, or at work.

Some vacuum flasks come with additional features such as built-in filters, handles, cups, and easy-pour spouts. They are popular for their efficiency in retaining temperature, durability, and portability.