Pinpoint Conductivity Monitor by American Marine. **** PRODUCT MANUAL **** PINPOINT Conductivity Monitor™ is an instrument for the measurement of hardness in freshwater. The conversions are 33 µS=17.9 ppm=1dH. Good quality reverse osmosis water measures 5–15 µS, while de-ionized water typically measures 0–1 µS. The Conductivity Monitor is automatically temperature-compensated and has two ranges, making it useful several different applications. Both freshwater fish keepers and those who use deionized/reverse osmosis systems often rely heavily on this meter. The freshwater hobbyist will appreciate the instant readings for precise hardness. The saltwater hobbyist will use the PINPOINT Conductivity Monitor™ to assess the purity of deionized and reverse osmosis water. * Given proper care, the PINPOINT Conductivity Monitor™ should last a lifetime. * PINPOINT Conductivity Probe is permanent and may never require replacement. * Powered by a standard 9-volt battery (not included).