Pyrex Borosilicate Glass 25ml Volumetric Flask - Class A Certified, Flat Bottom with PE Stopper & Glass Stopper - Labware for Chemistry Experiments, Scientific Research & School Labs (Pack of 12)

These 25mL volumetric flasks exceed the current standard (ASTM E-542) for manufacturing volumetric flasks because each individual flask is verified to meet the Class A volumetric tolerances in ASTM E-288. Each flask is also labeled with a lot number enabling you to access a Certificate of Analysis with lot specific data regarding both measurements and methods, trace your glassware and track usage. The strength of these flasks results from the use of machine blown bodies which are sealed to heavy-tubing necks. The graduation line is sharp and permanent. All flasks are provided with both a No. 9 Standard Taper PYREX and Polyethylene stopper.