This 2800 ml wide mouth PYREX® Fernbach-style culture flask is designed for culturing organisms requiring a large surface area to volume ratio. It can also be used in serum production. Triple baffled on the bottom outside edges to achieve maximal oxygen transfer to culture medium. Beaded neck rim is approximately 60 mm I.D. and accepts cotton plugs or No. 13 rubber stoppers. This flask has a large marking spot.