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. 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. 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 "ON/OFF"to open and use it,and just need to "ON/OFF"to close it. Digital TDS tester and PH tester both have the function of ATC,the measuring data 't be influenced by the water temperature,no matter testing the TDS or PH of the water. TDS tester and PH tester have small size and low weight as pen,they are easy to be carried,and convenient to take it in your pocket when you go out. Color:yellow + blue Material:plastic + metal Size:length 15.4cm Package Contents: 2 x TDS meter 2 x PH meter 4 x PH Calibration Packets 4 x User's manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.