Molecular sieves are special devices that contain porous media, with consistent, uniform pore size, specialized for separating molecules on the basis of their size and shape. They are often used for dehydrating gasses as well as for filtering liquids. Some sieves are specialized to adsorb certain molecules preferentially on the basis of their polarity. We carry highly efficient sieves here, capable of excellent moisture-retention rates, some of which are capable of drying gasses to a dew point of as low as -100.