Widely used in aquariums, fishponds, pharmaceutical research, agriculture, laboratories, water environments, and quality control applications. Features include easy operation, high accuracy, quick installation, and user-friendly design. Supports 3-point calibration with automatic identification for EC (1413 µS, 12.88 mS, and 111.8 mS). Built-in calibration points: 1413 µS/cm, 12.88 mS/cm, and 111.8 mS/cm. pH calibration options: 1-point (6.86), 2-point (6.86 and 4.00 or 6.86 and 9.18), or 3-point (6.86, 4.00, and 9.18), with automatic recognition of calibration solutions. This professional water quality tester offers simple operation, compact size, and portability. Includes automatic temperature compensation. Automatically powers off after 5 minutes of inactivity to conserve battery life. Battery not included. Specifications: Type: With backlight or without backlight (optional) Material: ABS EC Range: 0 to 10,000 µS/cm, 10.01–19.99 mS/cm, 20.1–400 mS/cm EC Resolution: 1 µS/cm; 0.1 mS/cm EC Accuracy: ±2% of reading TDS Range: 0 to 1000 ppm, 1000 to 10,000 ppm, 10.1 to 200.0 ppt TDS Resolution: 1 ppm; 0.1 ppt TDS Accuracy: ±2% of reading Salinity Resolution: 0.01% Salinity Accuracy: ±0.01% to 5.00% (±0.1%), 5.10% to 25.00% (±1%) pH Range: 0.01 to 14.00 pH pH Resolution: 0.01 pH pH Accuracy: ±0.05 pH Operating Environment: 0 to 60.0°C (32.0 to 140°F); RH 100% TDS Factor: 0.4 to 1.0 Temperature Range: 0.1 to 60.0°C (32.0 to 140°F) Temperature Accuracy: ±0.5°C Temperature Resolution: 0.1°C Battery: 3 x LR44, 1.5V, 160mAh Waterproof Rating: IP67 Display Size: 33 x 24mm Item Size: 180 x 37mm (7.1 x 1.5 inches) Item Weight: 86g (3.0 ounces) Package Size: 183 x 37 x 37mm (7.2 x 1.5 x 1.5 inches) Package Weight: 100g (3.5 ounces) Packing List: 1 x Water Quality Monitor Tester 3 x pH Buffer Powders 1 x pH Test Paper