22 buffer pre-programmed sets CMC for measuring in the optimum measuring range 5-point calibration A convenient pH/mV instrument for many applications: The pH 3210 is a portable precision pH/mV meter with an intuitive user interface. The unique Continuous Measurement Control (CMC) feature ensures that measured values and calibration ranges are within the optimum range, particularly useful for someone less familiar with pH measurements. The pH 3310 is an elegant combination of a portable meter and data logger for those who automatically save measurement data and want to further process data on a PC. Measurement characteristics and ease-of-use correspond to those of the pH 3210.