These 250mL 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. 200 polyethylene snap-caps. 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: 250mL. Flask style: volumetric. Flask shape: flat bottom. Top style: beaded rim. Neck style: long. Stopper style: no stopper. Flask feature: Lifetime red. Accuracy class: Class A. Tolerance: +/-0.1mL. Cap style: snap cap. Cap material: high density polyethylene. Cap color: blue. Snap cap number: No. 200. Height: 198mm. Outer diameter: 74mm. Corning #: 5600-250.