Serim® MONITOR™ for Chlorine 100-750 ppm test strips measure free chlorine. The test gives a semi-quantitative indication that chlorine-based sanitizers have the appropriate concentration of free chlorine required for use in sanitizing hard surface areas and equipment in numerous environments including food processing or preparation facilities, medical/nursing institutions, childcare or adult daycare facilities, schools and agricultural industries. A semi-quantitative estimation of the sanitizer's free chlorine concentration between 100 and 750 ppm can be made by comparing the color of the reacted indicator pad to the color chart on the bottle label. Color blocks free represent chlorine concentrations of 100, 200, 350, 500 and 750 ppm.