This 5-in-1 multifunction water quality test pen provides accurate measurements of EC (Electrical Conductivity), pH, TDS (Total Dissolved Solids), temperature, and salinity The device features automatic temperature compensation (ATC) to ensure accurate readings The test pen is equipped with a backlit display for easy reading in low-light conditions Its IP65 waterproof rating ensures durability and reliability in various environments Specification: EC test range: 0 to 10000uS/cm, 10.01-19.99mS/CM, 20.1-400mS/CM Resolution: 1uS/cm; 0.1mS/CM Accuracy: ±2% of reading Tds test 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 test range: 0.01-14.00pH Resolution: 0.01pH Accuracy: ±0.05pH Temperature compensation: Automatic temperature compensation (ATC) Working environment: 0 to 60.0℃ (32.0-140℉); RH 100% Temperature range: 0.1-60.0℃ 32.0-140℉ Temperature accuracy: ±0.5℃ Temperature resolution: 0.1℃/℉ Automatic shutdown: about 5 minutes Battery: 3 x 1.5V LR44 (included) Dimensions and weight: 183*37*37mm(7.2*1.5*1.5in)/90g(3.2oz) Display: Support backlight Waterproof grade: IP65 Power consumption: 2.9 mA, shutdown power consumption is 0 Note: The accuracy is relatively accurate within 150ppt, and the deviation is larger above 160ppt. Be sure to clean the electrode after each use.