Oil Pressure Sensor socket. Removes the OPS on 92-95 6.5 and 6.2 diesels.
Or any OPS that is not tucked up under the manifold as 96-00 6.5’s are in the factory location. In those 96-02 applications a 1 1/6″ “crows foot” may work or a plumbers “basin” wrench. With a basin wrench you will have to be very careful not to damage the new one.