Replaceable double junction electrode... use Testr body many times over, which saves you money Automatic Temperature Compensation (ATC) Push-button three-point calibration Microprocessor-based Auto buffer recognition Hold function; auto-off; error messages Certifiable to IP67 standards Never again watch your tester sink to the bottom of a tank or pond-”the OAKTON Double Junction pHTestr 2 floats! Unique double junction electrode design and increased reference gel volume give you significantly longer electrode life, especially in harsh applications. Automatic Temperature Compensation and three point push-button calibration provide high accuracy even under varying temperature conditions. Range -1.0 to 15.0 pH Resolution 0.1 pH Accuracy ±0.1 pH Calibration Up to three points (4.0, 7.0, 10.0) ATC Yes Electrode Replaceable double junction Waterproof/Dustproof (IP67) Yes Operating Temperature 0 to 50°C (32 to 122°F) Power Three 1.5 V batteries Battery life 24 hours continuous use Dimensions 6.5" x 1.5" dia (16.5 cm x 3.8 cm dia) Shipping weight 4.5 oz (125 g)