Description General description Class A, works certified • Complies with ISO 1042 and DIN 12664 • Calibrated to the tolerances required by the United States Pharmacopoeia (USP) which are tighter than those of ISO/DIN standards • Each flask engraved with individual serial number and supplied with certificate of calibration traceable to National standards • Conformity ‘H’ certified • Manufactured from borosilicate glass for corrosion-free performance • White enamel inscriptions • Polyethylene stopper Legal Information PYREX is a registered trademark of Corning, Inc.