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.

#7.5 Dimensions: 1 1/2” Bottom Diameter; 1 1/4” Top Diameter