Box Brew Kits 1 3 Piece Airlock and Drilled 6 Stopper Fermentation Beer/Wine Making Kombucha Fits Gallon Jugs

Fits perfectly! Universal size in my opinion. I make a lot of mead so I was in despair when I found out my dad had thrown my old airlock into the recyclables. I bought this as a last ditch effort hoping it would fit my 5 gal jug. Thankfully it does and works perfectly! The stopper it comes with is a bit too small (not horribly, just a tab bit off) but the airlock fits into my old stopper so I just use that instead.

Stoppers work good

Worked really well for the brewing process!! Cleaning it was extremely easy and the silicon stopper fit snugly into the gallon jug. Highly recommend and can't wait to use it for my next batch!

Very good quality item! Thanks so much!

The glass carboy is what it is. A good quality jug. But for the love of god throw the stopper out and buy new ones. Bout two of these and both stoppers were garbage. They don’t grip the bottle and slip out with pressure and trying to get them a little furth in to stay...plop. Right in the bottle. Definitely not size six as claimed or just crap quality. So if your thinking about saving money trying to combo, just buy the car boy and get the stopper elsewhere.