Airlocks let CO² out without letting contamination in. The Bungs fit Standard Glass Demijohns. Just half fill with water and you're ready to go.
10 x Fermentation Bubbler Airlocks & Bored Rubber Bungs Corks Demijohn Wine Beer
2 x Fermentation Bubbler Airlocks & Bored Cork Bungs - Demijohn Wine Beer
3 x Fermentation Bubbler Airlocks & Bored Cork Bungs - Demijohn Wine Beer
5 x Fermentation Bubbler Airlocks & Bored Cork Bungs Demijohn Homebrew Wine Beer
6 x Fermentation Bubbler Airlocks & Bored Cork Bungs Demijohn Wine Beer Cider
2 x Fermentation Bubbler Airlocks Bored Cork Bungs
