Made in the USA, Accu-Tab® three-inch calcium hypochlorite (cal hypo) tablets are quality-controlled through every step of the manufacturing process. The result is a high-performance erosion tablet specifically engineered for Accu-Tab chlorination systems. Together, the tablet and chlorinator act as an integrated system that consistently delivers chlorine to kill bacteria, help prevent RWIs, and maintain water clarity. Not Approved by the EPA for Swimming Pool Use. Potable / Industrial Water Chlorination