LaMotte 4331-H WaterLink SpinDisk Series 402 Single Use Reagent Cartridge 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!