Description General description • Complies with ISO 1042 and DIN 12664 • Calibrated to the tolerance required by the United States Pharmacopoeia (USP) which are tighter than those of ISO/DIN standards • Manufactured from borosilicate glass with an amber coating on exterior surfaces to facilitate use with light sensitive solutions • Each flask is laser etched with an individual serial number, batch code and date of manufacturer Legal Information PYREX is a registered trademark of Corning, Inc.