The PINPOINT II Calcium Monitor is an extremely accurate digital Calcium measurement instrument for marine saltwater aquariums. Powered by a 9-volt battery (now not included), the PINPOINT Calcium Monitor will operate for roughly 150 total hours before battery replacement is visually indicated at the display. Includes a solid state probe for increased stability, accuracy and longer life. Calibration is fast, simple and precise. In most cases used as a precision spot checking out instrument with imaginable continuous monitoring capabilities. Probe measures 7″” and has a 10 ft. cord. Calibration fluid is included.PINPOINT II Calcium Monitor Fluid Kit comprises 1 bottle each and every of 100 ppm and 1,000 ppm calcium calibration fluids.