DuraBreeze Carbon Filters keep the air in indoor gardens clean and fresh. Available in a variety of sizes, each filter contains a 2.5" pelletized carbon bed within a zinc-anodized steel housing. A pre-filter is also included, and all filters come with flanges attached. Each DuraBreeze Carbon Filter carries a one-year warranty, and has about a one-year life span. The 4" DuraBreeze Carbon Filter is effective up to 200 cfm, and has a diameter of 9.5" and a height of 12.5" including flange.