H7032L is a premium quality 1,382 mg/L (ppm) TDS calibration solution standardized with a conductivity meter that has been calibrated with potassium chloride NIST 2202 SRM (Standard Reference Material) in deionized water for analytiCalibration use in accordance with ISO 3696/BS3978. Additional equipment used in preparation of the solutions include certified weight-Checked balances, Class A glassware and certified thermometers.