If you are looking for pH meter buffer solution powder for precise calibration, this product meets your needs. Sealed packaging ensures practicality and long-term use. Each packet is individually wrapped to maintain freshness until use. Features - Color: Assorted - Material: ABS - Size: 7.00 x 6.00 x 0.50 cm / 2.75 x 2.36 x 0.20 in - Includes calibration solution powders for pH 4.01, 6.86, and 9.18, sufficient for daily pH calibration needs - Compact and lightweight individual packets allow for easy portability and storage - As a powder in sealed packets, it has no shelf life limitation—simply mix with distilled water before use - Easy to use—no measuring required; each packet is designed to be mixed with 250 mL of distilled water - Suitable for use in drinking water, pools, aquariums, and hydroponic systems Package List: 5 x pH 4.01 buffer powder packets 5 x pH 6.86 buffer powder packets 5 x pH 9.18 buffer powder packets