The Phat Filter is a professional grade, world renowned greenhouse filter that will remove the nastiest odors from your growing area. Phat filters use a very special charcoal carbon that comes from a source of pre-Cambrian ore, or some of the oldest carbon found on earth. This carbon dates back 250 million years and is the reason our Phat Filters are so effective! The special carbon is mined from deep within the earth, activated with steam at very high temperatures and shipped to us for use. No hazardous compounds ever come into contact during the activation process. Keeping our planet green and clean is what we are all about! Genuine Phat Filters offer you the quality you can trust through non-pelletized carbon, using no glues or binders thereby increasing the effective filtering capability of Genuine Phat Filters. Featuring RC 412 Charcoal Includes Prefilter Given CFM rating is for scrubbing. Divide by 2 to get exhaust filter CFM Characteristics of Phat Filters: * Highly effective, Low density virgin carbon * Carbon tightly-packed for increased porosity * Greater & more even air movement provided by internal, conical filter base * Manufactured so that no air blows by the filter without being filtered * Outer aluminum mesh provides 53% open area allowing increased air flow * Genuine Phat Filters are immediately sealed after manufacture to help retain moisture, optimize presentation and improve life expectancy