MORE CONVENIENT IN USING. 5 seconds to get the data of PH or PPM, know the water quality accurately. The pen meter partner also can be separately used whenever you need. WIDELY USED AND ACCURATE. Digital TDS meter has measurement range 0-9990ppm and ±2% accuracy, PH meter has measurement range 0.00- 14.00PH, 0.01PH accuracy and 0.01PH resolution. AUTO-OFF FUNCTION AND EASY TO USE. TDS pen meter and PH pen meter both have the function of Auto-off to save the battery’s life. The TDS meter and PH meter both are easy to use, just need to press “ON/OFF” to open and use it, and just need to press “ON/OFF” to close it. AUTOMATIC TEMPERATURE COMPENSATION ( ATC ). Digital TDS tester and PH tester both have the function of ATC, the measuring data won’t be influenced by the water temperature, no matter testing the TDS or PH of the water. SMALL SIZE AND POCKET PORTABLE. TDS tester and PH tester have small size and low weight as pen, they are easy to be carried, and convenient for you to take it in your pocket when you go out.