... moisture permeability. The main raw material of silica gel is a high-porous silica SIO2 structure of water, non-toxic, tasteless, odorless ... relative humidity of environment during the storage and transport. It can help prevent items from damp and moldy.Quality ... ,DMF free,natural resolved,2.Unidirectional absorption package 3.it has widely used in instruments,meter,equipments,leather,bags, ...