PYREX 50mL EZ Access Wide Mouth Volumetric Flask, Accuracy Class A, Heavy Duty, with Glass Standard Taper Stopper. Designed for microchemical work. The heavy duty, wide mouth facilitates filling and mixing. Permanent, sharp graduation line. Flask description: Volumetric, flat bottom, long neck, standard taper stopper top. Material: Borosilicate Glass Code 7740. Capacity: 50mL. Tolerance: ±0.05 mL. Height: 130mm (approx). Outer Diameter: 51mm (approx). Accuracy Class: A. Corning #: 5635-50.