The principle of insulating cup is that it has two layers of structure, the middle is in high vacuum state, which can block convection and heat dissipation. At the same time, the mirror function added in the bottle can effectively prevent the heat loss caused by radiation, thus keeping the liquid in the cup at a certain temperature.

① Sealability: Fill the cup with water, tighten the lid, and then invert it. If the cup does not leak, it proves that the cup is well sealed.

② Insulation performance: Pour boiling water into the cup, tighten the lid for a few minutes, then touch the cup with your hand. If the cup is hot, especially if the cup is hot, the insulation performance of the cup is not good.

③ Quality of accessories: Observe the appearance and accessories of the cup. If the cup body and inner liner are smooth, there are no burrs and scratches, and the plastic parts have no odor, the quality is good.

④ Material identification: The cup body 18/8 indicates that the stainless steel material contains 18% chromium and 8% nickel. The material that meets this standard is a green product in line with the national food grade standard. The product is rustproof and corrosion resistant.