Why we test at .027 micons		Hydrophobic Filters . Hydrophobic filter media is commonly used in airway management and typically composed of synthetic fibers like polypropylene.  Because the fibers are hydrophobic they do not absorb moisture from air flow.  Moisture and particulate collect on the fiber surfaces or pass through the filter.  This characteristic tends to limit the efficiency of devices relying solely on hydrophobic media because they do not adequately restrict the flow of moisture. Relative efficiencies will diminish as particles decrease in size (virus are smaller than bacterium) and when the filters are subjected to higher volumes of airflow or to use over a prolonged period of time, where moisture and particulate are able to migrate through the filter.
		Hydophilic Filters Hydrophilic filters are designed to absorb and retain moisture and particulate from air without compromising airflow efficency.  Although highly efficient in their own right they are able to provide even higher levels of viral and bacterial filtration efficiency when combind with hydrophobic filters because their inherent properties are so complimentary.  The moisture and particulates migrating through the hydrophobic filter are captured and contained within the hydrophilic layer of filtration. This principle forms the very basis for 2H Technology.   Each filter dramatically enhances the others efficiency as they act in concert to achieve unprecedented levels of performance and protection.