: 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 included. 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. Features: ? ??It can emit carbon dioxide for honey, white wine, milk wine alcohol fermentation and can prevent oxidation. ? ? ??Easy operation, simply 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. ? ? ??Effectively prevents flies flying into the wine/beer with a cover included. ? ? ??All of the fermentation process is automatic fermentation without manual control and can be repeatedly used for a long time. ? ? ??Suitable for pure juice fermentation, such as white grapes, honey wine fermentation, red wine secondary fermentation, etc. ? Specification: Material: Plastic Color: Transparent as picture Sub-Type: Airlocks Product Length: Approx. 17cm / 6.7inch Product Max Width: Approx. 1cm / 0.4inch Product Weight: Approx. 18g Package Included: 1 x Brew Check Valve