Description: This is a 5-in-1 multifunctional water quality testing pen that can measure pH, TDS solubility, EC conductivity, salinity, and temperature. It is an IP67 waterproof water quality testing pen that integrates five functions. Replaceable probe, delivery of calibration powder package, automatic calibration at 3 o'clock.Measurable Salinity (Sea Salt/Freshwater Salt): Sea Salt: The salinity of sea water is the ratio of total dissolved solids to the weight of sea salt in sea water, usually expressed in grams per kilogram of sea water. ( Measurement range: 10.1-200.0 ppt) Freshwater Salt: Water with a salt content less than 0.5g/L (measurement range: 0.00-25.00%, accuracy: 0.01%-5.00%, 5.10%-25.00%)Product Parameters: Conductivity Test Range: 0-10000 μS/cm, 10.01-19.99 mS/cm, 20.1-400 mS/cm Resolution: 1 μS/cm; 0.1 mS/cm Accuracy: ±2% of reading TDS Testing Range: 0-1000 ppm, 1000 ppm-10000 ppm, 10.1-200.0 ppt Resolution: 1 ppm; 0.1 ppt Accuracy: ±2% of reading Salinity Measurement Range: 0.00-25.00% Resolution: 0.01% Accuracy: 0.01%-5.00% (±0.1%), 5.10%-25.00% (±1%) pH Testing Range: 0.01-14.00 pH Resolution: 0.01 pH Precision: ±0.05 pH Temperature Compensation: Automatic Temperature Compensation (ATC) Operating Environment: 0-60.0℃ (32.0-140℉); RH 100% TDS Factor: 0.4-1.0 Temperature Range: 0.1-60.0℃ (32.0-140℉) Temperature Accuracy: ±0.5℃ Temperature Resolution: 0.1℃/℉ Automatic Shut-off: Approximately 5 minutes Battery: 3 × 1.5V (LR44) Bare Metal Size and Weight: 183 × 37 × 37 mm (7.2 × 1.5 × 1.5 in) / 90 g (3.2 oz) Packaging Size: 236 × 80 × 50 mm / 170 g Display: Backlight support Waterproof Rating: IP67 Power Consumption: 2.9 mA, shutdown power consumption is 0 Accuracy Note: Relatively accurate within 150 ppt, significant deviation above 160 ppt Attention: Clean the electrodes thoroughly after each use