PX-I,PX-IA(BNC),PX-II,PX-III(ATC) Mini pH Meter Range: 0--14 pH, Accuracy: ±0.1 pH, Resolution: 0.1 pH, Temp.°C: 5--50°C, Calibration: Two-point at 4.01pH and 6.86pH, Battery Life: DC 4 x .5V