The pore size for 4A molecular sieve is 4A. It is mainly used to adsorb water, methanol, ethanol, sulfureted hydrogen, carbon dioxide, ethylene, propylene, does not adsorb any larger molecular than 4A, and often used as desiccant in industrials. Typical applications: 　　 Deep drying of air, natural gas, alkane and refrigerant 　　 Generation and purification of argon 　　 Static dehydration of electronic element, pharmaceutical and unstable materials 　　 Desiccant for paint, dope and foul etc.