This economical, easy to use, hand held, pH pen has the following features: Auto calibration, a microprocessor-based pH tester that assures fast and stable readings, an accuracy of ± 0.1 pH, an automatic temperature compensation for better accuracy, a large easy-to-read LCD, easy one or two point automatic calibration and a splash proof screen. Specifications Range: 0.00 to 14.0 pH Resolution: 0.1 pH Accuracy: +/- 0.2 pH Temp. Compensation: Automatic Battery Life/Type: 300 Hours / 4 x 1.4 v Environment: 0˚ to 50˚ C / 95% Relative Humidity Dimensions: 6.5" x 1.5" x 1" Warranty: 2 Year