PH Meter Digital 0.01 High Precision Water Quality Tester with 0–14 Measurement Range for Aquarium, Swimming Pool, Drinking Water, RO Systems, Spas, and Hydroponics Note: Batteries and calibration powder are not included. This pH meter is suitable for household, laboratory, and general-purpose use, including testing the pH of drinking water, swimming pools, aquariums, food-related applications, reverse osmosis (RO) systems, spas, and hydroponic systems. Specifications: Measuring Range: 0.00–14.00 pH Resolution: 0.01 pH Accuracy: ±0.01 pH Power Source: 2 × 1.5V LR44 batteries Automatic Temperature Compensation: 0–50°C (32–122°F) Dimensions: 15 × 2.5 × 1.3 cm (6 × 1.1 × 0.5 in) Net Weight: 52 g (1.83 oz) Calibration Instructions: Step 1: Turn on the pH meter. Rinse the electrode with distilled water. Step 2: Immerse the electrode in pH 6.86 standard buffer solution. Step 3: Press the “CAL” button. Wait until the display stabilizes at 6.86 pH. Step 4: Rinse the electrode with distilled water and gently dry it. Then immerse it in pH 4.00 standard buffer solution. Step 5: Press the “CAL” button. Wait until the display stabilizes at 4.00 pH to complete calibration. Step 6: Rinse and dry the electrode, then immerse it in pH 9.18 standard buffer solution. Verify the reading falls within 9.17–9.19 pH. Calibration Powder Information: pH calibration powder is a solid standard reference material. Dissolve in distilled water as directed to prepare standard buffer solution. Each packet prepares approximately 250 mL of solution. Follow the specified water-to-powder ratio precisely to ensure calibration accuracy. Precautions: The pH probe contains glass components and is fragile. Avoid impact or contact with hard surfaces. Handle with care. After each use, gently blot the probe dry with absorbent paper. Note: The device is factory-calibrated before shipment. Recalibration is not required upon initial use unless one of the following applies: - Extended usage since last calibration - Frequent electrode use - High-precision measurement requirements