How to choose a good vacuum flask

Buy branded products: Generally, brand thermos cups have instructions. Various materials and parameters are indicated on the instructions. You can choose thermos cups based on these data.

Observe the inner and outer surface quality of the vacuum flask: a good vacuum flask generally has smooth inner and outer plate surfaces without scratches and bumps. At the same time, pay attention to whether the mouth of the cup is smooth and whether there are welds.

Test the insulation performance of the thermos: After filling it with boiling water, turn the cork or lid clockwise, and then touch the surface and bottom of the cup by hand after 2 to 3 minutes

If the cup body and the upper part of the cup body are found to have obvious warming phenomenon, it means that the inner liner of the thermos cup has lost its vacuum degree and cannot achieve a good insulation effect.