Features: Accurately test the purity of water in your home. Through testing the water total dissolved solids value or the conductivity of water to judge the purity or the pollution level of water. Also has water temperature and environment temperature measurement function. It can be widely used in water-treatment industry, drinking water industry, home, travel, field work and so on as a water quality inspection and discrimination tools. Soluble salts, calcium ion, and etc.. Ionic organic compounds, ammonium acetate, sodium sulfate, etc.. Heavy metal ion chromium, zinc, copper, etc.. Usually, the lower the total dissolved solids value is, the less soluble salts and heavy metal ions in the water, and the purer the water is.