Economy portable pH meter, 2 points calibration, automatic temperature compensation, system menu contains 2 optional parameters.
The meter is used for measuring the pH and millivolt of samples. Accuracy: 0.01pH.

Features:
* Stability indicator automatically shows current measurement status.
* Auto-Hold function freezes stable reading for easy viewing and recording.
* Automatic electrode diagnosis shows offset and electrode slope.
* Reset feature automatically resumes parameters back to factory default options.
* Help message as a operational guide that helps you quickly using the meter(for PH-220).
* Manual temperature calibration improves the measurement accuracy of meter(for PH-320).
* Selectable temperature unit (°C or°F ) meets different application requirements(for PH-320).

pH Mode (For PH-221/320):
* 1 to 5 points push-button calibration with auto-buffer recognition.
* Automatic electrode slope display helps user decide whether to replace sensor.
* Automatic Temperature Compensation provides accurate measured values.
* Calibration Due Reminder prompts you to calibrate the meter regularly.

ORP Mode(For PH-221/320):
* 1 point offset calibration allows adjusting the displayed value to a known standard.
* Relative and absolute mV measurement modes provide accurate ORP readings.

Ion Concentration Mode(For PH-320):
* 2 to 5 points calibration providing the 8 concentration points can be selected.
* Automatically recognize ion electrodes, does not need to specify the type of ion.
* Direct ion concentration readout simplifies the elaborate measurement process.
* Selectable multiple concentration units include the ppm, mg/L and mol/L.