Premium quality breathable silicone bung, designed to fit most small barrels and plastic carboys. This bung offers the additional benefit of having an “airlock mode” which can allow CO2 blowoff during alcoholic or malolactic fermentations, and then can be sealed completely by pressing the center plug all the way into the bung.

Dimensions are 1 7/8″ upper diameter and 1 1/2″ lower diameter.