Oakton (WD-35624-70) Deluxe pH Calibration Kit W-O MeterOakton WD 35624 70 Deluxe pH Calibration Kit Without Meter NIST traceable buffer solutions and calibration essentials for accurate pH measurement in laboratories and field applications NIST Certified Standards 0. 01 pH Accuracy Freshness Dated MSDS Included The Oakton WD 35624 70 Deluxe pH Calibration Kit provides everything needed to maintain pH meter accuracy except the meter itself. Each buffer solution is standardized against NIST certified