4A Zeolite has a pore size of 4A, which absorbs water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, and does not adsorb any molecules (including propane) with a diameter greater than 4A. The selective adsorption performance of 4A  Zeolite for water is higher than any other molecular. 4A molecular sieve is one of the most used molecular sieve desiccants in the industry.