Pyrex Borosilicate Glass Class A 50ml Volumetric Flask with Standard Taper Stopper - Flat Bottom, Lifetime Red - Laboratory Grade Precision Glassware (Case of 12) | Perfect for Chemistry Experiments, School Labs & Scientific Measurements

These 50mL Class A PYREX Lifetime Red volumetric flasks have the capacity mark etched as a fine line through a narrow red band into clear glass, making a filler unnecessary and giving high legibility, accuracy and permanence. The strength of these flasks has been increased appreciably through machine-blown bodies to which are sealed heavy-tubing necks tooled for No. 9 Standard Taper glass stoppers. For replacement stoppers see No. 7650. These Class A 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. Calibrated "to contain."