These rubber stoppers with pre-drilled holes are essential for sealing carboys, flasks, or fermentation vessels while allowing an airlock or tubing to be inserted. Available in a range of sizes (#2 to #10), they fit various openings and are made from durable, food-safe rubber.

Perfect for homebrew and laboratory use, they ensure a tight seal while enabling gas release during fermentation. Pair them with airlocks or blow-off tubes for controlled fermentations.