For use with eXact Photometers, the eXact Strip Micro Total Hardness Low Range incorporates the patented eXact reagent delivery system created by Industrial Test Systems, Inc. which is ideal for technical and non-technical users. By dipping the eXact strip into a photometer cell, the exact amount of reagent is released into the water causing a change in color or turbidity. The change is measured by an eXact photometer giving the user fast and accurate results. Each unit consists of a bulk bottle of 50 tests.