Premium Corning Pyrex 5640-25 Borosilicate Glass 25mL Volumetric Flask (±0.03mL) - Class A Flat Bottom Heavy Duty Lab Glassware with Standard Taper Stopper (6-Pack) - Perfect for Chemistry Experiments, Laboratory Measurements & Scientific Research

These PYREX 25mL test tube shaped volumetric flasks provide improved lab convenience - broad selection - and precise volume measurement. 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. The graduation line is sharp and permanent and large white block letters make the inscription easy to read. 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. Material: borosilicate glass code 7740. Capacity: 25mL. Flask style: volumetric. Flask shape: flat bottom. Top style: standard taper stopper. Neck style: long. Stopper style: hollow glass. Standard taper stopper number: No. 9. Flask feature: heavy duty. Accuracy class: Class A. Feature: reusable. Tolerance: +/-0.03mL. Height: 121mm. Outer diameter: 40mm. Corning #: 5640-25.