Features: As a tool to improve your quality of life. It can be used for drinking water testing, swimming pools, aquarium PH balance, RO system, spa or hydroponics. Basically, all environments that need to test the PH value can use this tester to get accurate data. Let you no longer worry about whether your ph meter is accurate, the calibration packages we give can help you check if our ph meter is accurate. pH Meter: Full pH Measuring Range -2.00-16, Reliable and Fast Readings.3 in 1 TDS Meter: Measuring Range 0-9990ppm, 0-9990μs/cm;, You Can Mention Them ± 2%, 0.1- 80.0 °C, 32.0-176.0 °F. Lightweight, Handy Design for Portability and Convenience. Specification:Material: ABS Size: 155x3 2mm/ 6.1x1.3 inch, 150x2 0mm/ 5.91x0.79 inchPackage Included:1 × TDS Meter (Battery Included)1 × ph Meter (Battery Included)3 ×PH Powder Buffer2 ×User User ManualNote: Please allow 1-3cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.