The Phosphorus Ultra Low Range Checker® HC Calibration Check Set provides a simple solution to validating the Phosphorus Ultra Low Range Checker® HC - HI736 that has a range of 0 to 200 ppb as phosphorus. This high-quality set of standards is manufactured in our state-of-the-art facility and comes supplied with a Certificate of Analysis. The Certificate of Analysis provides the lot number, reference values and expiration date for traceability when certifying the Checker® HC. - Supplied with Certificate of Analysis - Standard value of 100 +/- 10 ppb phosphorus @ 25°C - Reusable with long shelf life stability