The Ohaus ST3100MB Starter 3100M Bench Meter, with Stand-Alone Electrode Holder & In-Use-Cover helps you save time, space and money, which combines all your pH, ORP, conductivity, TDS, salinity, resistivity and temperature measurements - in one smart device. Ideal for a wide range of lab applications, the ST3100MB is incredibly easy to use. Equipped with software to ensure the reliability of your readings, and RS232 connectivity to store and transfer data conveniently, the ST3100MB is a great addition to your lab.