Widely used in aquarium, glass fishpond, mining, pharmaceutical research, agriculture, laboratory, water environment, colleges and universities, quality control and other fields. Features: A set of 2 instruments is convenient for you to detect water quality. The digital PH pen is equipped with automatic temperature compensation function. You can use the bufferpowder to calibrate the tester. TDS meter has locking and automatic turn off functions (please note: this meter cannot test seawater.) Press the button, it can display the data of water purity level in PPM (part per million) on the screen. Also this instrument can test water temperature. Easy to use, accurate measurement results, accurate and stable readings can be displayed in a few seconds. Compact, convenient to carry and convenient to use. LCD backlight display for clear reading, support night monitoring. Specifications: TDS&EC Meter: Color: blue Conductivity: 0-9999 us/cm ±2 Temperatures: 0.1-80 / 32-176 ±2 TDS: 0-9999 ppm ±2 Battery: 1 * CR2032, 3V, 240mAh Item size: 153 * 30 * 14mm / 6.0 * 1.2 * 0.6in Item weight: 44g / 1.5ounce PH Tester: Color: yellow+black Measure range: 0.00-14.00PH ±0.01PH Battery: 2 * LR44, 1.5V, 160mAh Operating temperature: 0-60 Item size: 153 * 30 * 16mm / 6.0 * 1.2 * 0.6in Item weight: 44g / 1.5ounce Package size: 160 * 60 * 60mm / 6.3 * 2.4 * 2.4in Package weight: 140g / 4.9ounce Packing List: 1 * TDS&EC Meter 1 * PH Tester 1 * PH TestPaper 3 * PH BufferPowder (4.01+6.86+9.18)