Silicone Ventilating Bung #13 (Dry Airlock)

Have you ever unwittingly created a vacuum in your plastic
fermenter (for example, while taking off the lid), causing the
old, funky water in the airlock to get sucked down into your
otherwise pristine fermented beverage? You can put an end to
such horrors once and for all by using silicone stoppers. These
stoppers create a one-way valve without any liquid, so they are
always worry-free. They also provide a superior seal, are very
durable, and can be sterilized in boiling water!

Dimensions:
O.D. Top – 2 5/8″
O.D. Bottom – 2 3/16″
Height – 1 1/4″