In winter, the stainless steel vacuum flask has reached the hot season again, and the vacuum flask has now become a good gift. There are so many varieties of stainless steel vacuum flasks on the market, which makes it difficult for consumers to distinguish whether the cup is insulated. Let's now talk about how to distinguish whether the stainless steel vacuum flask is insulated. Let me talk about the heat preservation principle of the stainless steel vacuum flask: Generally, the body of the kettle is divided into two layers: inside and outside, with air in the middle. The air is a poor conductor and therefore has a certain heat preservation effect. Larger, the water is more likely to change its taste, and it is not easy to carry. Nowadays, vacuum stainless steel vacuum flask is the best heat preservation method. The vacuum is to exhaust all the air in the middle, forming a thorough insulation layer inside to achieve a relatively strong heat preservation effect. The thermos cup uses stainless steel and a vacuum layer as a water container, and the top is sealed, so that the heat dissipation of the hot water inside will be slowed down, so as to achieve the effect of heat preservation. Read the instructions for use before buying a stainless steel vacuum flask. Do not buy Sanwu products. In terms of price, generally very cheap vacuum flasks do not have insulation quality assurance, and the price of stainless steel vacuum flasks with thermal insulation performance will not be very cheap. Do not buy inferior products for cheap. Generally, the instructions for the thermos cup will have a method for identifying the insulation performance. The specific method is as follows: first scald the cup with hot water, and then connect a full cup of hot water, put the lid tightly closed and leave it for 24 hours, then pour it out and test the water temperature to know if it is warm. The stainless steel vacuum flask produced by Xinyi Industry and Trade, the inner and outer container adopts automatic welding and Japanese tailless vacuum technology to prevent the heat exchange between the inner container and the outside, and has a long heat preservation effect; the lid and the bottle body are sealed with a round mouth and food grade. Silicone is added to the seal to completely prevent leakage. Is the best gift you buy.