Features: Easy to Use: Simply immerse the pH meter electrode in the solution to be tested, readings are quickly display on a large LCD display. Auto Calibrated: Just press a button to finish the calibration. Fast and Accurate Results: No need to work with those annoying color charts and test strips. Compact Portable Design: Total concealed fit in your bag or pocket for easy, casual carrying. Wide Application: Ideal instrument for any aquarium, the fishing industry, swimming pools, spa, school laboratories, food & beverage, drinking water etc. Operation: 1. Remove protective cap and protective film on the screen. 2. First rinse the electrode with distilled water, and suck it with filter paper. 3. Turn the meter on by pressing the "ON/OFF" key. 4. Immerse the pH meter electrode in the solution to be tested can not be over the immersion line. 5. Stir gently and wait around 30 seconds till the reading stabilized. 6. After finishing, clear the electrode with pure water turn the meter off by pressing "ON/OFF" key. 7. Always replace the protective cap after use. Note: Recalibration is required in the following conditions: 1. Lengthy periods of inactivity; 2. Very frequently use; 3. The testing accuracy requirement is very high; 4. The "CAL"(calibration) button was pushed and electrode exposed to air for extended period of time. Maintenance: Always replace the protective cap after using digital meter to keep electrode from drying out due to prolonged exposure to air, which leads to slow or unstable reading. If electrode has been dries out immerse it into distilled water for a few hours. Specifications: Model: pH-2 Pro Material: ABS Measure Range: -2.00~16.00pH (generally in 0.00-14.00pH) Calibration Mode: 3-point auto-calibration Resolution: 0.01pH Accuracy: ±0.01pH Power Supply: 2 * 1.5V (LR44 button cell) Operating Temperature: 0~80 / 32~176 Calibration: two points automatic calibration Reset Function: Turn it on, Press the ON/OFF key for 3 seconds, and then release it. When "----" appears on the screen, the reset is successful ATC Function: Automatic temperature compensation function Power-off Storage Function: The data will be automatically saved after the battery is pulled out and stored for one month Litmus Test Function: The color of the LCD will change according to the pH value, just like a litmus test Stripe Item Size: 155 * 32 * 18mm / 6.10 * 1.26 * 0.71in Item Weight: 58g / 2.04oz Package Weight: 120g / 4.23oz Package Size: 17 * 5.5 * 3cm / 6.69 * 2.16 * 1.18in Package List: 1 * pH meter 3 * Calibration Powder 2 * Button Cell 1 * User Manual (English)