The main composition of silica gel is silicon dioxide(SiO2). It is a kind of porous substance with a specific surface area of 700 square meters / gram. When saturated with water, the surface will not humid and the shape will not change.The chemical formula is SiO2+nH2O, it is a material with good stability and high security. It is regarded as a dietary supplement by America FDA. Under certain relatively humidity, it can be divided into A and B type according to the moisture absorbing rate. A-type is used widely, mainly used for waterproof or rustproof packages in the food products and electronic fittings etc. B-type is mainly used to adjust humidity and to prevent condensation of water sweat.The moisture absorbing capability and physical chemistry’s performance of our products conform to the standard of Japanese Industrial Specification (JIS-Z-0701).