Active Air Carbon Filter, 12" x 39", 1700 CFMActive Air Carbon Filter is the ultimate solution for all your air purification and ventilation needs in your grow room. Virgin activated Australian granular carbon absorbs volatile organic compounds, impurities, and odors that pass onto its micro porous carbon surface. Each filter is light in weight, machine packed, and comes with a pre filter. It is equipped with powder coated bases and tops. The open air mesh is built to ensure better airflow.