The Organic Air IGS4HEPA 4-inch HEPA filter has been manufactured using opposing dual cone technology that optimizes airflow even as it traps and filters out 90 percent of molds, insects, and bacteria. With the Organic Air Filter protection, your indoor garden provides just the kind of contaminant-free conditions your plants need to grow to their full potential. It's much more beneficial to use a 4-inch filter with a 6-inch fan because HEPA filters need the air flowing as fast as possible. In order to do this, you should step up the fan or blower size and use a duct reducer to attach your HEPA filter to the blower. This 4-inch HEPA filter is easy to clean. Just remove the filter, rinse from the inside out, and let it air dry.