Feature 1As long as the probe is immersed in the nutrient solution, the instrument will measure automatically. 2Suitable for hydroponics, fish tank, aquariums, farmland, swimming pools, aquaculture, laboratories and industrial wastewater. 3EC, CF and PPM can be measured and high conductivity measurements can be made for a variety of crops without recalibration. 4Compact pen-shape design, lightweight for mobility, you can test water anywhere to get the purest water. 5The water temperature is automatically compensated to 25 during the measurement, it can provide you with an accurate and stable reading.Condition: 100% Brand NewItem Type: Water Quality TesterMaterial: ABSMeasuring Range:0.4~5.2EC 4-52cf 280~3640ppm (EC x 700) 200~3000ppm (EC x 500)0.4-4.4EC 4-44cf 280-3080 PPM (EC x 700) 200-2200 PPM (EC x 500)140-2520ppm (EC x 700) 100-1800ppm (EC x 500)Accuracy: 4%Resolution: 0.1ec 1cf 70ppm 700 50ppm 500Operating Temperature: 0~50 (32~122F)Battery: 3 x AA Battery (not included)Size: Approx. 415 x 23mm / 16.3 x 0.9inWeight: Approx. 243g / 8.6ozOperation:1. Heat the sensor head and put the probe into the nutrient solution for 1-2 minutes to reach the temperature of the nutrient solution.2. Measure electrical conductivity, simply remove the rod from the solution and place it back in place for 1-2 seconds.3. Read the conductivity value, remove the rod from the solution, and read the indicator light value on the valve stem..w-e-text table td,.w-e-text table th,.wang-edit-text table td, .wang-edit-text table th{border: .5pt solid #000;};.w-e-text table,.wang-edit-text table{border: 1px solid #000 !important;}Package List1 x Water Quality Tester1 x InstructionNotePlease allow 1-3cm error due to manual measurement. Thanks for your understanding.