The Green Line is Kootenay Filter Inc.’s Lightweight Filter Line. KFI is proud to have a product that uses only virgin activated carbon made from renewable resources. The proven design, manufacturing process and a production staff with years of experience make our product one of the best filters on the market. Our Light line filters are available with flange sizes 4"-14" rated for 250 – 3250 CFM . Our filters consist of only 2 things, steel and carbon; they are effective and robust. These Carbon filters are specifically designed for the control of VOCs (Volatile Organic Compunds), odors, and other gaseous contaminents.