7-Piece Rubber Bung Stoppers with Airlock Hole for Homebrewing, Fermentation, and Science Experiments

When it comes to fermentation, the key is to keep the oxygen away. This rubber stopper may look pretty simple, but it plays a very big role within the process. Constructed from a solid rubber material, this stopper features a perfectly sized hole to fit an airlock. Simply insert this stopper into the mouth of your fermenter or carboy, add the airlock, and you have an oxygen free zone.

#7 Dimensions: 1 17/16” Bottom Diameter; 1 3/16” Top Diameter