ACCURATE AND RELIABLE: To achieve high accuracy, equipped with premium titanium alloy probe and reliable automatic temperature compensation, the reading is always accurate at different temperatures. MULTIFUNCTIONAL AND IMPROVED: Professional TDS, EC and temperature pen 3 in 1. Upgraded with a large backlit LCD screen for easier reading and an auto-lock function for easier operation. EASY & INSTANT: Just turn on the TDS meter and gently stir water, then the stabilized readings will be automatically locked on LCD screen in seconds, and the tds ppm meter will automatically turn off if not used for more than 2 minutes. MULTI-PURPOSE TDS TESTER: Test the purity of drinking water to ensure it is healthy, monitor if the reverse osmosis (RO)/DI system is working properly, if the filter needs to be replaced, aquarium maintenance, hydroponics (test nutrients ), swimming pool and spa, etc. Note: The data is manual measurement, please allow 1-3cm error, due to the differences between light and screen, there will be a certain color difference, the specific received in kind prevails.