A-AF25290 Filter, Air, Primary Magnum RS (QTY 1)One New Aftermarket Replacement Primary Air Filter (Fleetguard Magnum RS AF25290) This Fleetguard (Cummins Filtration) Magnum RS primary air filter (AF25290) is a radial seal element designed to protect engines operating in demanding agricultural, construction, and industrial environments. The Magnum RS series uses cellulose filtration media engineered to trap damaging particles and deliver reliable engine protection across extended service intervals.