A-AF25412 Filter, Air, Secondary Magnum RS (QTY 1)One New Aftermarket Replacement Secondary Air Filter Fleetguard AF25412 Magnum RS This secondary (inner safety) air filter is a Fleetguard Magnum RS radial seal element designed to protect the engine from fine particulates that bypass the primary filter. It serves as the last line of defense in two stage air filtration systems used on construction equipment, agricultural machinery, and other heavy duty applications. The Magnum RS radial seal design