It can release carbon dioxide and be used in the fermentation of , 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 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: Airlock Colour: transparent color + red + black Material: PP Size: about 170x10mm Package Contents: 10 * check valves 10 * 10 * sealing rings Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real . The measurement allowed is +/- 1-3cm.