The PFHB bi-directional filter filters fluids in both directions and is not another high pressure that filters in one direction and has reverse flow check or bypass valve built into the housing.  Max recommended operating pressure 6200 psi / 450 bar makes the PFHB ideal for protecting large cylinders or hydrostatic loop circuits.  In large cylinder applications fluid is typically trapped in the lines and never makes it back to the reservoir.  With the PFHB in-line between cylinder and reservoir this can go from one of the dirtiest systems in a plant to one of the cleanest ensuring cylinder reliability