This "Singles" Buffer Solution Pouches Assortment Pack includes 5 pouches of each solution: pH 4.01, 7.00, 10.00 and deionized Rinse Water. pH "Singles" pouches are convenient, air-tight pouches with high-precision calibration standards. Ideal for field use-take them to your test site for on-the-spot calibration. Pouches are labeled with a pH vs. Temperature chart and CAS numbers for "Right-to-Know" requirements. To ensure quality, all are freshness dated and standardized against NIST-certified references within 0.01 pH at 25 °C.