Hanna pocket pHep tester has 0.0 to 14.0 pH range, 0.1 pH resolution, accuracy +/- 0.1 pH and deviation due to electromagnetic field + 0.1 pH, suitable for field use, manual calibration, standard of two calibrations 4.01 / 7.01 or 10.01 pH, four 1.5V alkaline batteries, works continuously for approx. 1700 hours.