A low-profile filter comprising: a filter housing adapted to mount on a surface mount substrate, the surface mount substrate being a passage block with an inlet and an outlet that define a communication passage adapted to provide fluid communication to and from the low-profile filter, the filter housing having a plurality of flow paths (414, 416, 418) and a filter cavity defined therein, wherein a first flow passage is defined to connect an inlet at a first surface of the filter housing to a first section of the filter cavity; wherein a second flow passage is defined to connect a second section of the filter cavity to an outlet at a second surface of the filter housing; and wherein the first and second surfaces are on obverse sides of the filter housing; characterized in that the filter housing being a unitary piece of material and having a pass-through flow passage defined therein to connect a bottom port at the first surface of the filter housing to a top port at the second surface of the filter housing, the pass-through flow passage being a pass-through passage bypassing the filter cavity, wherein the inlet, the outlet, the bottom port and the top port are configured and spaced in the unitary piece of material of the filter housing to interface with corresponding ports of the surface mount substrate and a component mounted on the low-profile filter; wherein the filter cavity is generally tubular and wherein an axis of the filter cavity extends in parallel to the first and second surfaces, wherein the filter cavity is connected to a lateral port in the filter housing through which a tube filter assembly is inserted into the filter cavity and wherein the filter cavity is separated by the tube filter assembly into adjacent sections including the first section of the filter cavity and the second section of the filter cavity, the filter assembly being disposed coaxially within the filter cavity. a filter housing adapted to mount on a surface mount substrate, the surface mount substrate being a passage block with an inlet and an outlet that define a communication passage adapted to provide fluid communication to and from the low-profile filter, the filter housing having a plurality of flow paths (414, 416, 418) and a filter cavity defined therein, wherein a first flow passage is defined to connect an inlet at a first surface of the filter housing to a first section of the filter cavity; wherein a second flow passage is defined to connect a second section of the filter cavity to an outlet at a second surface of the filter housing; and wherein the first and second surfaces are on obverse sides of the filter housing; characterized in that the filter housing being a unitary piece of material and having a pass-through flow passage defined therein to connect a bottom port at the first surface of the filter housing to a top port at the second surface of the filter housing, the pass-through flow passage being a pass-through passage bypassing the filter cavity, wherein the inlet, the outlet, the bottom port and the top port are configured and spaced in the unitary piece of material of the filter housing to interface with corresponding ports of the surface mount substrate and a component mounted on the low-profile filter; wherein the filter cavity is generally tubular and wherein an axis of the filter cavity extends in parallel to the first and second surfaces, wherein the filter cavity is connected to a lateral port in the filter housing through which a tube filter assembly is inserted into the filter cavity and wherein the filter cavity is separated by the tube filter assembly into adjacent sections including the first section of the filter cavity and the second section of the filter cavity, the filter assembly being disposed coaxially within the filter cavity.