Reusable, non-absorbent, white foam stoppers provide a snug fit, yet allow free airflow. Ideal for Erlenmeyer flasks when propagating yeast cultures.

• Autoclavable up to 249F (121C)
• Fits 35-45mm inner diameter openings in graduated cylinders, tubes, and flasks
• Easily manipulated -springs back to original shape after use
• Resists alcohols, bases, esters, and dilute acids