Filter King fuel pressure regulator replacement Diaphragm.
Please ensure this is the correct one for your filter king as there are 2 different sizes, the FK67 and the FK85
The FK67 has a 4-screw pattern and the FK85 has a 6-screw pattern.
This diaphragm is for the 4-screw pattern, FK67 regulator.
The larger diaphragm, for the FK85 regulator is here