4A molecular sieve is refers to the type A sodium aluminosilicate, 4 A molecular sieve adsorption critical diameter is not more than 4 A molecule, can adsorption water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, etc,all can be on type 3 A molecular sieve adsorption of molecules, can adsorption in 4 A type.4 A molecular sieves for water adsorption performance than any other molecules, the choice of one of the largest varieties of molecular sieve is industrial use. Heavy metal content is lower than the eu RoHS standard and SONY GP.