The Chlorine DPD #3R RAPID TesTabs® Tablets are specifically designed for measuring total chlorine levels in pool and spa water using electronic colorimeters and photometers. The #3 instrument grade indicates the specific formulation of the DPD reagent, providing highly accurate measurements in total chlorine detection. The RAPID formula contains a disintegrant for faster reaction times and quicker results. These tablets enhance measurement accuracy and offer consistent performance, making it easy to achieve quick and clear results with compatible devices. Pack contains 250 tablets.