describe: Easy to use: Just dip the pH meter electrode into the solution to be measucolor and the reading is quickly displayed on the large LCD display Wide Application: Ideal instrument for any aquarium, fishery, swimming pool, spa, school laboratory, food and beverage, drinking water, etc. Auto Calibration: Features built-in calibration using 2 buffer powders. Calibration is done with the push of a button. This pH meter is factory calibrated. Users can use it directly. Fast and Accurate Results: No need for those annoying color charts and test strips. Resolution: 0.01 pH, Accuracy: 0.01 pH COMPACT PORTABLE DESIGN: Pocket pH meter is lightweight and compact. Completely concealed in your bag or pocket for easy casual carry. Specification: Display: LCD digital Accuracy: 0.01 Resolution: 0.01 Working temperature: 0~60 Measuring range: 0.00~14.00 Probe type: Precision glass ball electrode Power supply: 2 1.5V LR44 batteries (not included) Clarification: Step 1. Remove the protective cover. Step 2. First rinse the electrode with distilled water and blot dry with filter paper. Step 3. Press the ON/OFF key to turn on the meter. Step 4. Immerse the pH meter electrode into the solution to be measucolor (should not exceed the immersion line). Step 5. Stir gently and wait approximately 30 seconds until the reading stabilizes. Step 6. After completion, clean the electrode with pure water and press the ON/OFF key to turn off the meter. Step 7. Be sure to close the protective cap after use. instruct: 1. Turn on the pH meter 2. Dissolve each buffer solution in 250ML distilled water 3. Immerse the electrode in the pH 6.86 solution (temperature 25C) 4. Press and hold the CAL (Calibration) button for 5 seconds and release -The display will start flashing 6.86 - Wait for the display to stop flashing. Rinse the electrode with distilled water and dry with filter paper. 5. Immerse the electrode in the pH 4.00 solution, - Press and hold the "CAL" button for 5 seconds, then immediately press and release a second time - Reading will start flashing at 4.00 - Wait for the display to stop flashing Rinse and dry the electrode with distilled water as before. 6. Place the meter back into the buffer solution to test the calibration. If incorrect, recalibrate 7. If the approximate pH of the test solution is known to be above 7.0, calibrate the meter using the 6.86 and 9.18 solutions. To do this, follow the calibration chart. The third step is the calibration method at 9.18 points. Packaging contents: 1 piece of pH testing pen notes: 1. Due to differences in monitors and light effects, the actual color of the item may be slightly different from the color shown on the picture. 2. Please forgive 1cm/0.39in-3cm/1.18in measurement deviation due to manual measurement.