All home brewers know that a buon vino carboy bung is a step up from an ordinary rubber stopper. each buon vino bung features extra-long tapered sides that help create an airtight seal for your fermenting brew and a handy ridge that prevents the bung from accidentally being pushed into the carboy. the pre-drilled hole accepts all styles of airlock and the bung dimensions are the same as a regular #10 rubber stopper so you can use it with three, five, and six gallon plastic carboys. *please note: also available without the airlock hole by clicking here. *. in stock and ready to ship. features: made of rubber. airlock hole fits all kinds of airlocks. extra-long taper to create a tight seal. protruding lip to prevent accidental drop into carboy. same measurements as #10 rubber stopper. fits 3, 5, and 6 gallon plastic carboys. specs: dimensions: 1 5/8" bottom diameter.