These Pyrex® Erlenmeyer Flasks from Corning are narrow-mouth flasks with approximate graduations marked by in durable white enamel. An extra large marking space is also provided. Heavy, durable top tooling. Flasks with capacity from 10 mL to 6,000 mL are available. This convenience pack contains one each of the most popular sizes of Cat. No. 4980 flask. Designed for the low volume user. A case contains one each of five sizes: 50 mL, 125 mL, 250 mL, 500 mL, and 1 L.