pH Continuous MonitorProvides months of inexpensive, carefree continuous monitoring. In-line pH electrode, single junction, without ATC All push-button microprocessor-based operation... no trimpots to adjust! Includes double junction pH electrode Three point pH calibration at pH 4, 7 and 10 Auto buffer recognition automatically identifies correct buffer for rapid calibration Bright red LED display is easy to read from a distance Built-in AC power adapter for long-term monitoring Checking pH levels once a day might not be enough to prevent a serious problem in your water quality application. The OAKTON pH Continuous monitor features a bright red display that lets you check your pH levels at a glance.Range 0.0 to 14.0 pH Resolution 0.1 pH Accuracy ±0.1 pH Calibration Three-point (4, 7, 10) Temperature Compensation No Power Built-in AC adapter Faceplate Standard and Hydroponics Dimensions 3.4" x 3.4" x 1.25" (8.6 x 8.6 x 3.2 cm) Shipping weight 0.5 lb (0.23 kg)