The adjacent picture is the front side and back side of a ZP sensor, when using these sensors it is important that the connector you use does not cause a short between the front side and backside. If you are planning to use these sensor in a potentiometric mode you of course need to make electrical connection with the working/sense electrode, you can then choose to use the reference or counter electrodes as your reference or short the counter and reference together and have them combined as the reference electrode.
