1. The material is food-grade silicone rubber, non-toxic, tasteless, safe and environmentally friendly, and meets the standards of daily necessities in contact with food in Germany and the United States.^2. High and low temperature resistance, operating temperature range -50 ~ +250 , can be used in refrigerators, microwave ovens, electric ovens. Due to the excellent elasticity of silica gel, the internal negative pressure is naturally formed when the container is covered, which completely isolates the flow of internal and external gas, and has good sealing performance. It is used in the refrigerator to cover bowls, pots, basins, etc., and will not odor, because it completely isolates air from entering, it can achieve the best preservation effect.^3. The thermal conductivity is as small as 0.27, which is about 1/1000 of that of metal. It is used to cover bowls, pots, basins and other heat preservation effects.^4. The silica gel composed of silicon-oxygen bonds is super resistant to aging and has a service life of more than 30 years under normal conditions.