Description Fleetguard AF25135M is a primary Magnum RS radial seal air filter element for heavy-duty diesel engines, used as the outer air cleaner element in Caterpillar equipment, Challenger tractors and other construction and agricultural machinery. It has a cylindrical cartridge design with approximately 390 mm length, 315 mm outer diameter and 208 mm inner diameter, and cross-references Caterpillar 6I2505, Donaldson P532505, Baldwin RS3510, Fram CA7480, Luber-finer LAF4505 and WIX 46593.