This 5-in-1 high-precision digital water quality tester can be used for the following applications: food salinity, aquaculture, drinking water, laboratories, swimming pools, fish tanks and other water quality testing. Fish tank PH/salinity tester: monitor the growth environment of fish, prevent and treat fish diseases, purify water and maintain water cleanliness, suitable for freshwater fish, marine fish, ponds, etc. Monitor the PH/EC value of hydroponic nutrient solution to that plants have a suitable growth environment. Swimming pool pH salinity tester: ideal range for saltwater swimming pools (pH: 72-7.8; salt: 2700-3400ppm). Check the TDS value of drinking water. The backlight design allows measurements in dimly lit environments. Colour:White+Green Material:ABS Package Contents: 1 x Water Quality Monitor 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.