Flask has 6 baffles, 3 baffles on the lower outside edge of the flask and 3 baffles on the bottom surface of the flask to maximize oxygen transfer to the culture medium when used on an orbital Shaker. Gray polypropylene vented cap has a 0.22Μm (PTFE) hydrophobic membrane to allow gas exchange while preventing contamination. They have a liner-less plug seal design for efficient sealing. They are autoclavable at 121°c. Since these caps are vented, the flasks can be autoclaved with the cap attached.