Handheld pH/mV meter that reads pH or millivolts alongside temperature on a dual LCD display. Its microprocessor auto-recognizes standard buffer solutions and supports 3-point calibration for accuracy, with automatic temperature compensation, a replaceable electrode module, and a protective rubber holster. Runs on a 9V battery (AC adapter sold separately) and can be used handheld or wall-mounted, with selectable C/F readout.