The PINPOINT Calcium Monitor™ is the only truly affordable and accurate digital Calcium measurement instrument for marine saltwater at this time. Powered by a 9-volt battery (not included), the PINPOINT Calcium Monitor™ will operate for approximately 150 total hours before battery replacement is visually indicated on the display. The PINPOINT Calcium Monitor™ comes complete with Calcium Meter, Calcium Selective Probe and Calibration/probe fluids. Given proper care, the PINPOINT Calcium Monitor™ should last a lifetime.