Silica gel is a granular, porous form of silica (SiO2) produced by synthesis of the sodium silicate. It has a high porosity, of about 800 m2/g, which makes it easy to absorb water, the silica gel is useful as a moisture absorber (desiccant). The silica gel can reduce the relative humidity to the closed system at 40%. When saturated with water can be regenerated (dried) by heating at 150°C. Silica gel is non-toxic, non-flammable and chemically highly inert. Silica gel can be supplied with ingredients moisture indicator that changes color after a silica gel saturated with moisture. Standard silica gel can hold the amount of water corresponding to about 20% of its weight.