With a Big Air Carbon Filter, gardeners get the great odor-reducing power for which Mountain Air is known, but with even greater air-moving capacity! Responding to customer requests, Mountain Air increased the airflow rating of the filter to approximately 516 cfm, shortening its lifespan to roughly two years. When attached to a ventilation system’s exhaust, it removes 99% of odor-causing organic particles in one pass. 10” flange included.