Easy to use: just install the Rubber Stopper with Hole with holes on the top of the Fermentation Plug container, insert the Fermentation Plug device into the rubber stopper, pour water water into the Fermentation Bubbler with Stopper device and close the lid to ferment red wine. One-way valve design: Fermentation Bubbler with Stopper is designed to insulate well air during secondary fermentation to avoid oxidation, and allow the whole fermentation process to proceed automatically and discharge at room temperature without manual control. Our fermentation bubbler group has a wide range of applications, which is very suitable for food preservation, cabbage, kimchi and sauerkraut fermentation, as well as for brewing wine, beer, sake, etc. The Reusable Fermentation Plug does not require manual control and is easy to clean, which is very useful for red wine fermentation. Made of safe, non-toxic plastic and silicone. Features: Product name: fermentation bubbler Material: food grade silicone and high quality plastic Size: Fermentation Bubbler with Stopper: 170 * 10 mm / 6.69 * 0.39 in Color :white Package Contents: 3PCS x Fermentation Bubbler