A circular disk covered in rubber or plastic with a hole in the center where the edge is sometimes tensioned by a spRing that prevents fluid from leaking at the Mass Air Flow Sensor. Air Filter Housing Gasket. Fuel Injection Air Flow Meter Gasket / O-Ring. Mass Air Flow Sensor O-Ring. Part serviced with Air cleaner assembly. cleaner ASSEMBLY o -. Filter Housing Gasket. Fuel Injection Flow Meter Gasket / O -. Included with: Air cleaner assembly.