4A molecular sieve activated powder is a dehydrated synthetic zeolite powder with an effective pore opening of about 4 angstroms. It selectively adsorbs water and other small molecules such as CO₂, H₂S, methanol, and ethanol, while excluding larger compounds. This makes it a versatile desiccant for drying air, refrigerants, natural gas, and various solvents. It is also widely used as a moisture scavenger in polyurethane, coatings, and sealants to prevent defects, offering high adsorption capacity, excellent dispersibility, and chemical inertness.