Specifications: Measuring range: 0.00-14.00PH Accuracy error: ±0.01PH Resolution: 0.01PH Working temperature: 0℃-80℃ Calibration method: 2 points automatic calibration Electrode: glass bubble Temperature compensation: ATC automatic temperature compensation Net weight: Approx. 48g Battery: 2*1.5V (LR44 button battery) Dimensions: 155mm*29mm*16mm How to use: 1. Cut open the plastic bag, pour the powder into a 250ML volumetric flask, rinse the inner wall of the plastic bag with a small amount of CO2-free distilled water, and dilute to the mark and shake well. 2. The shelf life of the calibration solution is 2 years. 3. As long as the calibration solution is not contaminated, it can be reused. The shelf life after adding water is about 6 months. 4. After the calibration powder is converted into calibration solution, follow the steps below↓ How to use the calibration solution: 1. Wash the pH meter electrode with pure water (2-3 times); 2. Immerse the pH electrode in a mixed phosphate standard buffer solution with a pH value of 6.86 (25°C), and shake gently; 3. Press the cal button to calibrate until the displayed value matches the pH value of the standard buffer solution at ambient temperature; 4. Rinse the electrode with pure water first, and then insert the electrode into the standard buffer solution of potassium hydrogen dicarboxylate with pH 4.00 for calibration; 5. After about two minutes. The displayed value should be within the allowable error range compared to the pH value of the buffer solution. 6. The so-called two-point calibration is to use two kinds of calibration solutions, and the three-point calibration is to use three kinds of calibration solutions. Generally, the calibration starts from 6.86. And then using 4.00. Operation Steps: 1. Remove the protective cover. 2. First clean the electrode of the pH meter with distilled water. And wipe the electrode dry with filter paper. 3. Turn on the switch located on the battery compartment. 4. Insert the pH meter into the liquid to be tested until the liquid is immersed to the "immersion line", if conditions permit, the solution can be immersed to a position slightly higher than the "immersion line". 5. Gently stir the solution and wait for about two minutes. Read the displayed value. 6. Finished use. Clean the electrodes. Turn off the switch. Put on a protective case. Precautions: 1. Please note that the PH pen probe is a glass product, which is fragile. 2. Please do not hit it with anything. Once damaged, it cannot be replaced. 3. Be sure to protect the probe well, and use absorbent paper to gently dry the water on the probe after use. . Package Included: 1X PH meter with opp bag, 3X Calibration Solution, 1X Instruction Manual. Battery installation: 1. If the brightness of the backlight decreases significantly or the displayed value is blurred, the battery should be replaced. 2. When replacing the battery, pull out the battery compartment to replace, pay attention to the polarity of the battery.