Kingplast Big Size LCD Display Dual Digital TDS Meter with 3 Buttons, Measure TDS (0-9990ppm) and Temp, Suitable for Household Drinking Water, Aquarium Pool Water, Swimming Pools, Hydroponics, Spa, Laboratory and Scientific ,Tds & Temp Meter Hold function,it is easy to read and record, press "HOLD" button then remove from test solution KINGPLAST words is printed on the TDS pen. We guarantee it can be used more than one year. seven minute Auto Shut Off feature, so battery won't run down and protect your meter Digital dual test meter, measure TDS, shift Degrees Celsius to Fahrenheit, absolutely with ATC Large LCD screen, quickly readout in 10 second, a portable leather bag and protective cap