LaMotte WaterLink® 4334-H Series 501 Chlorine/Bromine/pH Combo 3 Test Series Reagent Disk 50 per Box. For use with the WaterLink® Spin Touch® Photometer for Pool and Spa Water Analysis The innovative WaterLink® Spin Touch® photometer does all your water testing for you. Each sealed SpinDisk™ reagent cartridge contains the precise amount of reagent needed to run a complete series of tests. Now analysts can achieve test results without time consuming test and clean-up procedures. This ground-breaking analysis system is so simple anyone can use it! No vials to fill, no prep time, no guessing! Sold in boxes of 50.