Carbon filters are no longer just for the intake side of your air filtration system. Now they can be installed in-line with the lights and fans. The Phresh 701175 6-inch in-line carbon filter is built into an air tight conserving body that is capable of filtering 500 CFM. With built-in flanges, the Phresh in-line filters are state of the art carbon filters that scour the air to clean it of foreign particulates, dust, organic compounds and odors. Phresh Inline Filters last twice as long and are twice as light as other filters of the same size.