This PH buffer powder and buffer solution is a simple and easy solution to calibrating your electronic pH meter. This solution is compatible with most meters, and frequent calibration will help to ensure the accuracy of your PH readings. Perfect for testing PH balance of drinking water, pool, aquarium, Spa, or hydroponics. This buffer powder will work with any electronic PH Meter. Features: This calibration buffer powder for PH meter is Individual sized PH buffer packets that can be tucked in drawer, bag or suitcase for travel. Easy to use: open the packet mix the powder with 250ML distilled water. This buffer powder will work with any electronic pH Meter. Individually wrapped to maintain freshness until use. Produced with premium quality material under strict conditions, pre-measured. These buffers are accurate to within ±0.01pH units at 25°C and remain stable over long periods of time. Specifications: Type: Set A, Set B (optional) Accuracy: ±0.01PH at 25°C PH buffer powder: 4.01, 6.86, 9.18 4.01: Often used under acidic conditions, 4.01 standard solution should be calibrated 6.86: Often used under neutral conditions, 6.86 standard solution should be calibrated 9.18: Often used under alkaline conditions, 9.18 standard solution should be calibrated Item weight: 2.7g / 0.1ounce Package size: 60 * 50 * 10mm / 2.4 * 2.0 * 0.4in Package weight: Set A: 22g / 0.8ounce Set B: 46g / 1.6ounce Directions for Use: Step 1: Open the packet pour the powder into a cleaning dry glass cup. Step 2: Add 250ml deionized water (or distilled water) to the glass cup. (or a 250 ml calibrated flask) Step 3: Stir until the powder has completely dissolved. Step 4: Calibrate your PH meter. (rinse the meter by pure water before test) Notes: 1.To ensure more accurate , calibrate by 2 solution, first use 6.86, then 4.01 or 9.18. 2.Cup should be glass or ceramic, don't use metal material. 3.You can store the calibration solution in covered jars or glass cup for 2-3 weeks. (In the refrigerated condition) Packing List: Set A: 2 * 4.01 PH Buffer Powder 2 * 6.86 PH Buffer Powder 2 * 9.18 PH Buffer Powder Set B: 5 * 4.01 PH Buffer Powder 5 * 6.86 PH Buffer Powder 5 * 9.18 PH Buffer Powder