Provide automatic calibration at the press of a button. This probe is fast and dependable. Simply open calibration solution, dip the probe inside, and within seconds, the meter recognizes the calibration solution and self-calibrates. Perfect for hydroponics, water testing, reverse osmosis and aquaculture, this meter features a resolution of 1 ppm (mg/L) and an accuracy of ±2% full scale. Features include automatic temperature control, automatic calibration, and auto shut off. Two 1.5V batteries, included, provide 200 hours of continuous use. Range: 0–1999 mg/L. Size: 7" x 2" x 1".