Active Air Carbon Filter, 4" x 14", 215 CFMActive Air Carbon Filter is designed with virgin activated Australian granular carbon (RC 412) to safely remove bad odors, impurities, and harmful gaseous contaminants from the air. It helps you keep the air in your grow area clean and fresh. Powder coated aluminum bottom and top make the air filter light in weight. Each carbon filter is machine packed that allows minimal movement and more carbon. It also comes equipped with a pre filter and flange.