Usage Tips:FAST AND ACCURATE READINGS: water quality testers are manufactured to ultra-high standards,TDS meter ranges from 0-9990ppm. The tds meter digital water tester delivers fast and accurate readings with just a simple turn on,dip about 1 inch deep into the water,and instantly read the large digital display. SENSITIVE PROBE: The TDS Water Tester is equipped with a high quality probe,simply turn on the TDS meter and gently agitate the water,a stable reading will automatically lock onto the LCD within seconds,and the TDS meter will automatically turn off if not operated for more than 5 minutes. ACCURATE MEASUREMENT: The TDS meter has an auto-calibration function that can be adjusted according to the water temperature and water quality to measure the total dissolved solids (TDS) in the water.Once the value is stabilized, press and hold HOLD to stabilize the value and know exactly when to change the water filter. LIGHTWEIGHT & PORTABLE: Our water quality tester handheld design,small and convenient,can be easily put into a pocket or bag,any occasion can use electronic tester.Such as garden hydroponics,agriculture,beer brewing,aquariums,swimming pools,home drinking water,etc. Colour:blue Material:plastic Package Contents: 1 x Water Tester Only the above package content, other products are not included. Note: Light reflection 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.