The HI 98107 (pHep®), which is the result of over two decades of research and manufacturing experience, is the updated version of our widely popular 96107 (pHep®). Today the redesigned pHep series feature a rugged and ergonomically enhanced casing that fits comfortably in your hand and a larger LCD which makes it easier to read at any angle. With the latest innovation of a non-clogging fiber junction the new pHep meters last much longer. Simply pull out 1-2 mm (1/8") of the junction fiber to completely renew the junction. The pHep® offers a Range of 0.0 to 14.0 pH and an Accuracy of ±0.1 pH. This tester is calibrated manually to 2 points.