A. The fermentation tool you will receive consists of 3 plastic fermentation bubblers with lids and 3 rubber stoppers. It can meet your needs and allow you to use it freely. B. Our air barrier fermentation devices and rubber stoppers are made of food grade silica gel and plastics, which are safe and non-toxic and are suitable tools for food fermentation. C. The one-way valve of the fermentation stopper is designed to isolate the air well during secondary fermentation to prevent oxidation. The whole fermentation process is automatic and discharged at room temperature without manual control. Just put the rubber stopper with holes on the top of the fermentation tank, insert the fermentation bubbler into the rubber stopper, then pour water into the bubbler for fermentation and close the lid to start the fermentation of red wine. D. This fermentation bubbler has a wide range of applications. It is a good choice for preserving food, fermenting cabbage, kimchi, sauerkraut, and making wine, beer, mead, etc.