a fluid filter for the processing of a circulating fluid includes a unitary , molded plastic shell including an annular sidewall defining an open interior space and an annular entrance opening , the sidewall including an exposed edge that is formed with a plurality of recessed slots , a fluid filter cartridge inserted into the interior space of the shell and including a filtering media element and bonded thereto a molded plastic endplate . the endplate includes a plurality of outwardly - extending projections that cooperatively fit into said plurality of recessed slots for fixing the position of the fluid filter cartridge relative to the shell in terms of the axial depth of the cartridge into the shell and for preventing relative rotation or movement between the cartridge and shell .