Abstract: This disclosure illustrates a replaceable filter assembly for fluids in which the filter has a shell formed from an injection molded threaded end and an integral blow molded closed end to form a unitary shell. A seal such as a flange is provided adjacent to the threaded end so that a pressure seal can be maintained. A filter medium is supported within the shell so as to direct fluid flow through it to remove contaminants. The shell can be formed from plastic materials such as polyester terephthalate (PET), polyether sulfone (PES), and polyether urethane (PEU). This construction enables an inexpensive filter assembly and, with transparent plastic materials, an indication of the contaminant removal activity within the filter.