Xintao 4A Molecular Sieve, is an alkali alumina silicate. It is the sodium form of the type A crystal structure. It has an effective pore opening of about 4 angstroms(0.4nm). It will adsorb most molecules with a kinetic diameter of less than 4 angstroms and exclude those larger. Such as water, methanol, hydrogen sulfide, carbon dioxide, ethylene, propylene, and exclude those molecular adsorption diameter larger than 4A (propane, ethanol), the selection of water adsorption performance is higher than any other molecules.