It features a core of activated carbon that is sized to balance the dirt holding capacity of the filter paper to the dye removal capacity of the carbon core, in a ratio that is right for most systems using distillation to help remove solvent soluble contaminants. Designed and constructed to trap and hold substantially more insoluble soil than competing brands. Up to one third more usable surface area than other brands, with more premium filter paper and precise, deep pleating Puritan's extra surface areas holds more dirt and lasts longer. For superior removal of dye and other color impurities, only the best activated carbon granules are used. The core is vibratic packed to full capacity to ensure no settling occurs.