Widely used in aquariums, glass fish tanks, mining, pharmaceutical research, agriculture, laboratories, aquatic environments, universities, quality control, and other fields. Features: This set of 2 instruments is convenient for assessing water quality. The digital pH pen is equipped with an automatic temperature compensation function. You can use a buffer powder to calibrate the tester. The TDS meter has a lock and auto-off function (attention: this device cannot test seawater). Press a button to display the water purity level in ppm (parts per million) on the screen. This instrument can also measure water temperature. Easy to use, accurate and stable measurement results in seconds. Compact, easy to carry and use. Backlit LCD display for clear reading and night monitoring. Specifications: TDS tester and EC: Color: blue Conductivity: 0-9999 µs/cm ±2% Temperature: 0.1-80°C ±2% TDS: 0-9999 ppm ±2% Battery: 1 CR2032, 3 V, 240 mAh Dimensions: 153 x 30 x 14 mm Weight: 44 g Tester pH: