How to Use: 1. Take down the protective cap and press the ON/OFF button for turning on. 2. Put it into the ready to test solution, and the solution height should not exceed 4cm (from the probe end to start) 3. Stirring the measuring probe in the solution to be tested gently for stable data reading. 4. After use, please wipe and dry the probe with cloth, and put on the protective cover for storage.   Specifications: TDS Range: 0-9990ppm Temperature Range: 0-99℃ Accuracy: ±2% Battery Type: 2 * 1.5V LR44 Button Batteries(included) Size: Approx. 15.5*3*1.8cm/6.1*1.18*0.71in Weight: Approx. 70g   Package Included: 1 * TDS Tester   Note: 1.TDS (Total Dissolved Solids) is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular (colloidal sol) suspended form. 2.TDS measurements will influenced by temperature, therefore for temperature compensation to correct readings, please press the "hold" button for fixed numerical value in a few minutes. 3.The numerical value of TDS is bigger means the more water dissolve solids and the numerical value of TDS is smaller means the less water dissolve solids. Less the total dissolve solids, more purifying water for you. Features TDS meter measuring principle is to measure the electrical conductivity of water and indirectly reflects the TDS value Test the impurities in water such as some elements of soluble salts, ionic organic compound, heavy metal ion, etc, offering much convenience for you and your families to get a more clean water It supports hold function that can save measurement results for easy reading and record Automatic power-off function allows it to power off after 5 minutes without any operation in order to save power The TDS meter can be widely used for aquarium, beverages, quality control, fish hatcheries, food processing, laboratory, schools, colleges, swimming pools, etc