ST320 IP67 Starter pH ElectrodeOHAUS Precision Powers the Starter Electrodes The ST320 IP67 Starter pH electrode is ideal for sampling pH in the field. Compatible with the ST400 400M portable pH meters, the ST320 IP67 comes with a 3m cable and waterproofing. Backed by our commitment to accurate and precise measurement, the OHAUS Starter Series of electrodes are designed to produce exact results time and time again. The Starter Series includes pH, reference, oxidation reduction