The HI-97701C is an advanced portable photometer for the measurement of free chlorine in water.  This meter offers a superior optical system that utilizes a reference detector and narrow band interference filters for extremely fast and repeatable measurements. Chlorine is a common chemical used by many due to is disinfection, oxidation and bleaching properties. In swimming pools, drinking water, and food processing chlorine is used to disinfect and keep bacteria from growing. In metal finishing it used as an oxidizer to convert cyanide in wastewater to cyanate while in the pulp and paper industry it used to bleach wood pulp so that paper is white.  The HI97701 is designed to measure free chlorine in water up to 5.00 mg/L (ppm).The HI97701C has an innovative optical system that offers superior performance in accuracy, repeatability, and the short amount of time it takes to perform a measurement. This compact, waterproof meter is extremely user friendly with a tutorial mode that walks the user graphically, step by step, in performing a measurement. The use of a backlit dot matrix LED allows the use of virtual keys which makes the operation of the meter very intuitive including selecting different methods, reviewing GLP data, recalling the last 50 measurements, and customizing the meter to user preferences. HI97701C is completely waterproof including the cuvette holder that is designed with ridges to protect the optical path from getting scratched by the cuvette and a gasketed battery compartment that holds three common AA batteries. The compact design fits comfortable in the hand for use in the field or on a table for benchtop use. The LCD is 71 mm (2.75") by 37 mm (1.6") and is backlit for easy viewing under all conditions.