Abstract: The invention relates to a filter which is useable in conjunction with subsea hydraulic control circuits. The filters incorporated in a housing which can be stabbed in or out of a control unit to become part of one or more fluid control circuits. The stab-type housing can be inserted with a remotely operated vehicle. Other configurations involve long, slender housings for use with subsurface safety valve control lines as well as with tubing hanger housings. The slender design allows mounting right on the production tubing. A rupture disc feature is available so that if excessive pressure differential is obtained due to clogging, the filter unit within the housing can be bypassed to allow continuing operation.