Sensor Accessories Liquid Level Electrode OMRON ELECTRODE SENSOR CONNECTING NUT F03-02 SUS304, with excess: A Wide Variety of Electrodes for Long Lasting Reliability, and feature: Standard Electrodes are made of stainless steel (SUS 304) and can be used in applications for purified water., For applications where long electrodes are required, a connection nut and two Lock Nuts can be used to extend the electrodes 1 m at a time.