XIANQI Accuracy of measurement----The measuring range of the PH meter is PH 0-14, and the measuring range of the TDS meter is 0-9990ppm, 0-9990s/cm, Accuracy 2% [Professional use] The TDS meter tester can be used in water purifiers and filters, food (vegetable, fruits) drink quality monitoring, pools and spas, aquariums, hydroponics etc [Wide Application] Applicable industries: water laboratories, CDC, the aquaculture industry, hospitals, swimming pools, household tap water quality testing [Conversion Function] Press TEMP button can shift temperature meter between fahrenheit degree and centigrade degree. [Convenient Use] Hold function Saves measurements for convenient reading and recording. Auto-off function: Turns off meter after 10 minutes of non-use to conserve batteries quantity of delivery:1pc color of product:grey size of product:15.5*3.1*2.3cm