This air filter element removes particulate from the intake air stream before it enters the engine's combustion chambers. It sits inside the housing mounted on the engine, and the outer and inner diameters match the sealing surfaces of that housing to prevent bypass leakage. A restricted element increases intake restriction, which reduces engine power and raises fuel consumption. The manufacturer machines the sealing surfaces to match the housing's groove geometry so the gasket seats correctly and the element remains centered during vibration. On replacement, ensure the housing sealing surfaces are clean and that the element is fully seated before closing the cover.