Quantity: One Piece[4 in 1 Tester] This pH meter adopts a 4 in 1 design. With the numbers displayed on the LCD screen, you can know the PH, TDS, EC and temperature values of the water in a few seconds.[Accurate and Reliable] pH range 0-14, resolution: 0.01 pH, accuracy: 0.01 pH. TDS range is 1-9999 ppm and resolution is 1 ppm. EC range is 1-1999s/cm, resolution: 1us/cm, accuracy: 2%FS. Temperature measurement range: 0-60, resolution: 0.1, accuracy: 0.5.[Auto Power Off] In order to extend the life of the tester, we have designed an auto power off function. If it is inactive for 5 minutes, it will automatically shut down. In addition, it also has automatic temperature compensation and automatic calibration functions, and the readings are more accurate. [Portable] Dustgo pH meter is portable and lightweight, not only compact, but also easy to use. Suitable for testing the pH balance of drinking water, swimming pools, aquariums, reverse osmosis systems, hydroponics and SPA. [Calibration Method] pH: Put in the standard solution, press CAL to automatically calibrate (put in the standard solution 6.86, press the CAL button for 5 seconds, the calibration display 6.86 is completed); TDS: Put in the standard solution 1413, press the button for 5 seconds after CAL, it means the calibration 1413 is completed. (1413 is not included and must be purchased separately.)"