The responses above are provisional because one cannot assess the efficacy of a filter until it has been in service for quite a long time. In my case, the filter is preventing foreign matter entering the carburettors on an aircraft engine. The fuel is a 50:1 petrol and oil mixture that is alleged by some to be able to form a gum that clogs filters with paper elements. I searched in vain for information on the pressure drop vs fuel flow rate, which is critical in my application. Will the fuel pump be able to deliver enough fuel for a safe take-off after perhaps twenty hours' flying?