Corning® Pyrex® Volumetric Flasks with PTFE Stopper, Class A
By CorningClass A Pyrex® volumetric flasks have machine-blown bodies to which are sealed heavy-beaded, heavy-tubing necks, tooled for PTFE color-coded keyhole stoppers. The graduation line is sharp and permanent. Large white block letters make the inscription easy to read. These volumetric flasks have been manufactured to Class A tolerances as established by ASTM E- 694 for volumetric ware, ASTM E-542 for calibration of volumetric ware and ASTM E-288 for volumetric flasks.