Description: Include 1PH Meter & 1TDS Meter. and calibrated before leaving the factory. Both products need to be calibrated again after a period of use (this is a normal phenomenon, for PH, you need to purchase calibration yourself for calibration, while TDS needs to be calibrated in salt water) All use anti-oxidation PCB circuit board, which can be applied and stored in humid environment. High-definition backlit display, intelligent color change reminder, easy to obtain data. PH measure range: 0~14PH, Accuracy : 0.01 PH. The PH meter can tell you the acid-basic value. PH have the function of Automatic Temperature Compensation. TDS:0~9990 ppm, Accuracy:2%. 3 TDS meter can measure TDS, EC and Liquid Temperature in Fahrenheit or Degree Celsius. TDS is for testing the quality of water purifier with BACKLIGHT FUNCTION, convenience for you to read. The ph and TDS meter can test the hardness and pH of water, which can effectively ensure the quality and health of water. They are suitable for multiple occasions, such as drinking water, fish breeding, sewage testing, laboratories, plant cultivation, swimming pools, etc. Specification: Material: Plastic. Each Need Battery: 2x AA Battery(not include) Size Chart: TDS/PH: 155x15x30mm / 6.1x0.59x1.18inch. Package Includes: 1 Piece PH Meter. 1 Piece TDS Meter. Note: Color might be slightly different due to the color calibration of each individual monitor. Please allow slightly measuring deviation due to manual measurement.