Specifications: This product has automatic temperature compensation, which makes it convenient and practical. It has clear LCD screen with backlight function for convenient operation even in dark areas. It can be used for PH testing of liquid foods, tap water, laboratories, plant breeding, aquarium fish tanks, chemical sewage, aquaculture, swimming pools, agriculture, etc. (Related Knowledge: According to the published results of various cosmetic PH test values, the PH value is also one of the criteria for identifying the authenticity of cosmetics. If the PH value is not within the normal range, it means that the deterioration cannot be used) PH Meter Calibration: 1. Add a pack of 6.86 calibration powder to 250ML of water (distilled water/purified water/PH 7 water, normal temperature), and shake gently. Put the pen down and check the pH value of the solution. If it shows 6.8, the pen is accurate. 2. If the display deviates from 6.8, use a small screwdriver to adjust the calibration potentiometer (the small hole at the back) until the displayed value matches the pH value of the standard buffer solution at ambient temperature. When calibrating with 4.0 calibration powder, calibrate the pen to 4.0. Do not leave the detection pen on the water surface during calibration. Item Name: PH Meter Pen Material: ABS Testing Range: 0.00-14.00PH Resolution: 0.01PH, Precision: ±0.01PH (ATC) Automatic Temperature Compensation: 0-55 Celsius Degree Use Environment: Recommended 0 - 50 Celsius Degree, RH＜95% Power Supply: 4 x 1.5V Button Battery (Including Battery) Features: Portable, Easy to Read, High Precision, Water Tester Size: 15.3cm x 3.1cm x 2cm/6.02" x 1.22cm x 0.79" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. In the following cases, the PH meter must be recalibrated: 1. It has been used (or placed) for a long time after calibration; 2. When the electrode is used frequently; 3. When the measurement accuracy is high. Package Includes: 1 x PH Meter Pen 1 x Plastic Box 2 x Calibration Powder 1 x User Manual 1 x Small Screwdriver