The bt223 is 98% * 25 microns its nominal rating is 12 microns * 50% so it means on a single pass it will filter out 50% of particles that are down to 12 microns, The fleetguard has the same absoulute rating but they do not publish the nominal rating.

Valvoline vo106 is 98% * 20 microns. Nominal is 5 microns. You have to call But allmost to get the baldwin microlit media filters are the same rating.