ITEM NAME:Wine Seal Exhaust Valve Straw Home Brew Wine Fermentation Airlock Sealed Pl Y7S9 Wine Seal Exhaust Valve Straw Home Brew Wine Fermentation Airlock Sealed Pl Y7S9 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..Function:Brew One Way Valve,Brew Check Valve. 5 Brew Check Valve. Bar Accessories Type:Wine Check Valves. Model Number:Wine Check Valves.