Description: This item can emit carbon dioxide for honey, white wine, milk wine alcohol fermentation and can also prevent oxidation. It can effectively prevent flies flying into the wine/beer with a cover. All of the fermentation process is automatic fermentation without manual control, very convenient. It is easy to operate, you simply need to fill water into the exhaust valve, insert it to the cover of the brew barrel or rubber plug on the top of the fermentation container and then cover it with the lid. Suitable for pure juice fermentation, such as white grapes, honey wine fermentation, red wine secondary fermentation, etc. Specification: Condition: 100% Brand New Material: PPC Color: Transparent as picture Product Length: Approx. 17cm / 6.7inch Product Weight: Approx. 10g Package Included: 1 x Brew Check Valve It can release carbon dioxide for the alcohol fermentation of honey, white wine and milk wine, and can prevent oxidation. The operation is simple, just pour water into the exhaust valve, insert it into the lid of the brewing barrel or the rubber plug on the top of the fermentation container, and then close the lid. Wine Check Valve effectively prevents flies from flying into the wine/beer with the lid. All fermentation processes are automatic fermentation, without manual control, and can be reused for a long time. Suitable for pure juice fermentation, such as white grape, mead fermentation, red wine secondary fermentation, etc.