[ WIDE USAGE ]TDS water quality - Drinking Water,Laboratory,Hydroponics,Aquarium,Swimming Pool,RO/RD system,food & beverage, filtration system water,res tank ,spring water,ppm tested works well.[ ADVANCED 3-in-1 ]Smart pen combines TDS, , and a temperature meter for improved accuracy. With an Automatic Temperature Compensation and the measuring range of 0-9999 ppm +/- 2%, it is an extremely handy device to have around.[ TEST YOUR WATER ]How Pure is Your Water? With the push of a button, the TDS water tester can tell you your overall water purity level, which will be displayed on the screen in ppm (parts per million)[MEASUREMENT RANGE ]Easy-to-read backlit LCD screen,TDS: 0-9999 ppm Conductivity: 0-9990 s/cm Temperature range: 32-176Fahrenheit and 1-80Celsius. Battery: 1 x 3V Button Cell CR2032 Auto data-hold: lock and record readings Auto-off function for extended battery life , It is easy to use, the large back lit color-coded display is helpful and easy to read without glasses. It's light and fairly easy to carry in a pocket while working in the garden. Seems to be reliable[ WHAT IS TDS ]TDS = Total Dissolved Solids, which is any salt, metal or mineral in the water. The lower the TDS level in the water, the more efficiently your bodys cells can use the water. Conversely, higher TDS levels can indicate water that is more difficult for your body to use and has more contaminants that can pose health risks.Protable TDS& meter is a professional instrument with multi-function.Can be used to test water TDS(The weight of total dissolved solid of water,unit is mg/L or ppm).conductivity(the ability of conduction current expressed in digit,unit is us/cm) and the temperature.it has high performance,pen-type design,fast numerical stability and accurate result.Colour:yellowMaterial:plasticSize: 15.5 x 3cmPackage Contents:1 x Water MeterOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.