Fangrui Product Details 4-in-1 Multifunctional Water Quality Testing Pen That Can Measure Ph, Tds Solubility, Ec Conductivity, And Temperature. It Is An Ip67 Waterproof Water Quality Testing Pen That Integrates Five Functions. Replaceable Probe, Delivery Of Calibration Powder Package, Automatic Calibration At 3 Oclock. Measurable Salinity (sea Salt/freshwater Salt) And Stylish Design, Large Lcd Display, Display Support Backlight, Automatic Temperature Compensation (atc), Data Hold Function And Low Battery Indicator Conductivity Test (0-10000us/cm) Conductivity Is The Total Amount Of Dissolved Solids, Is A Measure Of The Ionic Conductivity Of The Water, The Reaction Of The Water Quality Is Good Or Bad Ez-9908 Is A Multifunctional Water Quality Pen Product, Which Can Measure Ph, Tds Solubility, Ec Conductivity, And Temperature. It Is A Waterproof Water Quality Test Pen With 4 Functions. It Has High Performance, Pen Shape Design And Fast Numerical Value. Stability And Accurate Calculation Results. Measuring Range:ph:0.00-14.00ph