Fastrack 3 Piece Airlock for Fermentation Hydrolocks for Fermenting Wine and Beer with Drilled Rubber Stopper Durable Carboy Bung with transparent Airlock Set used for Fermentation Set of 3

3 piece airlocks with #6. 5 rubber stoppers. (pack of 3 airlocks with 3 matching stoppers)use this airlock and stopper in your fermenter to create a closed system that allows co2 out and prevents harmful bacteria from getting in. fill to the marked line with sanitizer or boiled water. use with a drilled stopper. these stopper fit most gallon jugs and 38mm screw cap jugs.