... of calibrating up to 3 points usingUSA or NIST pH standard buffer.From Setup Menu, choose Calibration and immerse pH electrode ... the slope value, you decideswhether to change the pH electrode.AUTOMATIC TEMPERATURE COMPENSATION:Using the supplied temperature probe, the ... a computer via the USB port. METERS INCLUDED:pH Electrode, ORP Electrode (Only for SELON 221), pHStandard Buffer, Temperature Probe, ...