ST272 Starter pH ElectrodeOHAUS Precision Powers the Starter Electrodes The ST272 Starter pH Electrode is ideal for samples that require piercing or other semi solid sample types. 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 potential (ORP), conductivity, dissolved oxygen (DO), and temperature