New Creative Thermos Smart Temperature Display Stainless Steel Vacuum Flask Intelligent with LED temperature Touch Coffee Mug

A vacuum flask also known as a thermos is a container that can retain hot or cold liquids for an extended time. The basic idea of constructing the vacuum flask is that it focuses on the principles of thermal insulation, the idea of which is to provide as little route as possible by which heat could pass through it. 

This is a container with two layers- an outer and inner wall; commonly made of glass or stainless steel and sandwiching a vacuum space containing very little or no air. This vacuum layer lessens the heat transfer by conduction and convection to a great extent. The inner surface of the flask is generally covered with a reflective layer, for instance, silver to reduce loss by radiation.