This plastic cap fits any standard 38 mm jug and will accomodate either the 3-Piece or S-Shaped airlocks. Simply screw this onto a glass jug and insert an airlock for a small fermentation vessel. Used in place of a rubber stopper or bung.
These caps work with our 1 gallon clear jug, 1/2 gallon amber and clear jugs, and 1/4 gallon jugs.