Features: Just dip in the meter, stir, and get your results in seconds.It's compact and doesn'for t need any maintenance. TDS digital water tester can accurately and quickly check the heavy metal content, soluble salt content, ionic- organic matter, etc. In addition to the known reliable mineral water, other pure water needs to measure the purity of the water, which can protect the for health of children, the elderly and pregnant women. Small size and low weight as a pen-, they are easy to be carried, and convenient for you to take it in your pocket when you go out. Power supply: 2x1.5v button battery(included). Specifications: Material: Plastic Package size: 160x35x25mm/6.3x1.4x1in Power supply: 2x1.5v button battery(included) Note: 1. Take OFF the pen cover and turn on the 0N/OFF switch. 2. Put the pen into the solution to be tested. The height of the solution should not exceed 4cm(starting from the pen end). 3. Gently stir the pen in the solution to be tested for several times until the reading is stable. TDS measurements are highly influenced by temperature, so temperature compensation is required to correct readings. To manually lock the device, press the HOLD for key. If you need to retest-, press the CLEAR for key to CLEAR and then re-test. Press MODE for key to realize test function selection. 4. After use, dry the tip of the pen with a cloth and put the pen back in its holder. 5. Hold down the ON/OFF for key for 3S- to manually power OFF the device. Note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Water Quality Tester