The WL Spin is used by swimming pool companies to do detailed analysis of water composition. A water sample is injected into a reagent disc which is then inserted in the unit, where it get spun, thus distributing the water into reagent reaction compartments. The resulting changes in color are optically analyzed. We were responsible for the overall aesthetic design, assembly development, and all detailed design of the injection molded casework. Of particular concern was a design approach which assured proper alignment of the optical detectors to the reagent disc.