The HI 98129 Combo waterproof tester offer high accuracy pH, EC/TDS and temperature measurements in a single tester! No more switching between meters for your routine measurements. The waterproof Combo (it even floats) has a large easy-to-read, dual-level LCD and automatic shut-off. pH and EC/TDS readings are automatically compensated for the effects of temperature (ATC). This technologically advanced tester has a replaceable pH electrode cartridge with an extendable cloth junction as well as an EC/TDS graphite electrode that resists contamination by salts and other substances. This gives these meters a greatly extended life. Your tester no longer needs to be thrown away when the pH sensor is exhausted.The EC/TDS conversion factor is user selectable as is the temperature compensation coefficient (ß). Fast, efficient, accurate and portable, the Combo pH, EC/TDS and temperature tester brings you all the features you've asked for and more! Hanna #: HI 98129. Range (pH): 0.00 to 14.00 pH Range (EC): 0 to 3999 µS/cm Range (TDS): 0 to 2000 ppm Range (Temperature): 0.0 to 60.0°C / 32 to 140.0°F Resolution (pH): 0.01 pH Resolution (Conductivity): 1 µS/cm Resolution TDS 1 ppm Resolution (Temperature): 0.1°C / 0.1°F Accuracy (pH): ±0.05 pH Accuracy (Conductivity/TDS): ±2% F.S. Accuracy (Temperature): ±0.5°C / ±1°F Temperature Compensation (pH): Automatic; EC/TDS: automatic with ß adjustable from 0.0 to 2.4% / °C Calibration (pH): Automatic, 1 or 2 points with 2 sets of memorized buffers(pH 4.01 / 7.01 / 10.01 or 4.01 / 6.86 / 9.18) Calibration EC/TDS: Automatic, 1 point TDS Conversion Factor: Adjustable from 0.45 to 1.00 pH Electrode: HI 73127 (replaceable; included) Environment: 0 to 50°C (32 to 122°F); RH max 100% Battery Type / Life: 4 x 1.5V / approx. 100 hours of continuous use; auto-off after 8 minutes of non-use Dimensions: 163 x 40 x 26 mm (6.4 x 1.6 x 1.0") Weight: 100 g (3.5 oz.) HI 98129 is supplied with protective cap, electrode removal tool, batteries and instructions.