DiST testers are reliable, pocket-sized instruments that will give you quick and accurate readings of conductivity and TDS.This popular line of Dissolved Solids Testers have been redesigned to offer a host of improvements.The casing has been modified to provide increased strength, a better fit for holding and a large LCD for easy viewing. The graphite sensors provide better repeatability since they do not oxidize. The casing has been engineered to allow air bubbles to escape. The temperature sensor is exposed to provide faster response time.