Features: It can measure PH / TDS / EC / ORP / S.G/seawater specific gravity / temperature. The measurement range is large and wide and can measure freshwater salinity and sea salt. This product can detect the salinity of edible salt. At the same time, it can detect the salinity of seawater. Food salinity measuring range: 0.00-25.00%, seawater salinity measuring range: 10.1-200.0ppt. IP67 is an international waterproof and dustproof certification. Protection against dust intrusion, short-time immersion. Portable TDS meters can be carried anywhere to measure water quality such as tap water, RO system water, aquarium, seawater, pool water. The automatic power-off function turns off the power after 5 minutes without any operation to save power. Employs a fully transparent liquid crystal (LCD) to display 4-digit values and the corresponding physical quantity units. Specifications: Model: C-600A(with backlight) / C-600 (optional) EC: Measurement range: 0 to10000uS/cm 10.01-19.99ms 20.1-400mS/CM Resolution: 1 uS/cm; 0.1 mS/CM; Accuracy: ±2% of reading TDS: Measurement range: 0 to 1000ppm 1000ppm to 10000ppm 10.1 to 200.0ppt Resolution: 1ppm;; 0.1ppt Accuracy: ±2% of reading Salinity: Measurement range: 0.00 to 25.00% Resolution: 0.01% Accuracy: 0.01-5.00% (±0.1%) 5.10-25.00% (±1%) PH: Measurement range: 0.01-14.00pH Resolution: 0.01pH Accuracy: ±0.05pH ORP: Measurement range: 0~±999mV S.G:Measurement range: 1.000~1.222 Working environment: 0 to 60.0 ° C (32.0-140 ° F); RH 100% TDS factor: 0 .4to 1.0 Temperature range: 0.1-60.0 °C 32.0-140 °F Temperature accuracy: ±0.5°C Temperature resolution: 0.1 °C / °F Power source: 3x1.5LR44 ( not included ) Display size: 33*24mm Size: 183*37*37mm (7.2*1.5*1.5in) Weight: 105g (3.2oz) Package List: 1 * 7 in 1 meter 1 * manual in English 1.this item comes without retail box 2.Precautions Always clean the electrode after each use. 3.If the pH calibration does not identify the solution, the electrode is broken.