1、Working Principle: The TDS value of the water quality test pen represents the total soluble content in water, which can reflect the water quality. Usually the lower the TDS value, the less heavy metal ions and other soluble salts in the water, the purer the water quality. 2、LCD Digital Display: TDS water quality test pen with LCD digital display, more effective and intuitive, easy to read, accurate testing, rapid response. 3、Ti Alloy High Accuracy Probe: This TDS water quality test pen uses Ti alloy high accuracy probe, rust and corrosion resistance, sturdy and practical. 4、Test 3 Types of Impurities: The water quality tester can detect 3 types of heavy metal ions, such as zinc, copper, and other ionic organic substances; calcium ions, Mg ions and other soluble salts. 5、Indication Label: The TDS test pen has an indication label on the side, the test data can be compared with the indication label to understand the water quality condition.