The Cork Bung 1 Gallon Size Bored (10 pack) is a rubber bung with a pre-drilled hole designed to accept a standard airlock. It fits standard 1-gallon (4.5 litre) glass demijohns, which are widely used for small-batch wine, cider, and beer making. The bored bung allows CO2 to escape through the airlock while keeping bacteria out of your ferment.
Fit a Bubbler Airlock or Handy Airlock into the bored hole. Use with a 5 Litre Fermentation Vessel for small batches. Sterilise with Young's Steriliser before use.