The top measures 1 5/16″ and the bottom measures 1 1/16. These fit most standard glass fermenters! Fits almost all gallon jugs, 3 gal glass Carboys, and 5 gal glass Carboys.
Here’s TWO sets of TWO handy and necessary carboy stopper combinations to have for homebrew wine and beer – a 3/8″ holed #6 1/2 stopper to airlock your standard GLASS 3, 5, or 6 gallon carboy. Bungs it up much tighter than any other stopper. If fermentation is done or using for storage, remove the airlock and plug the 3/8 hole with the #000 stopper. You will get TWO large #6 1/2 stoppers and TWO small #000 stoppers.
199 in stock