It can release carbon dioxide and be used in the fermentation of honey, white wine, and dairy alcohol, 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 the lid.Effectively prevent flies from into the wine/beer with a lid.All fermentation processes are automatic fermentation, without manual control, and can be reused for a long time.Suitable for pure fermentation, such as white grape, mead fermentation, red wine secondary fermentation, etc.Subtype: AirlockColour: transparent color + red + blackMaterial: PPSize: about 170x10mmPackage Contents:10 * check valves10 * lids10 * sealing ringsOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.