This is a waterproof pH tester with large dual-level LCD that displays pH and temperature (?C or ?F). The large display shows readings in an extended range from 2 to 16 pH and simultaneously shows temperature from 5?C to 105?C or 23?F to 221?F. This tester has a stability indicator and hold function that freezes the display for easy and accurate recording. Complete with a temperature probe for faster and more precise temperature measurement, this tester compensates automatically for temperature. Calibration is made automatically in 1 or 2 points with memorized standards and NIST buffer sets. Auto power OFF saves battery power after non-use. The double injection electrode can be replaced in a very fast and simple way! The modular design allows easy electrode and battery replacement.