There should be an arrow or similar marking on the transparent casing. I have removed mine -- not able to find one small enough.The small m/c ones from Vehicle Wiring Products fit but the pressure from the bends in the fuel hose ends up bending the filter's outlet stubs and eventually they start leaking because of this. Any better ideas, anyone? Two right-angle hose connectors don't solve the problem completely and look pretty silly as well.