Flask has 6 bottom baffles to maximize oxygen transfer for bacterial, yeast and other cultures that require large amounts of oxygen for optimal growth. The 70mm vented cap has a 0.20Μm PVDF hydrophobic membrane to allow for sterile gas exchange while preventing contamination. A silicone liner ensures a tight seal between the cap and flask. A solid cap is available for anaerobic cultures. The flasks, cap and liners are all fully autoclavable.