Brewing airlock can be used for wine making, beer brewing, fermenting sauerkraut, that can satisfy your daily fermentation need. Simple to press the stopper onto the carboy, insert the beer airlock to the stopper, pour some water into airlock and cover the lid to complete all operations. Brewing airlock makes easier for the fermentation caused it could effectively isolate the air to prevent oxidation and allow the whole fermentation process to be automatic fermentation and exhaust at normal temperature without manual control. Note: Before use, please boil and disinfect the airlock with boiling water. Wash with water after use. size: 20 x 2cm Material: plastic colour: transparent Package Contents: 12 x Winemaking Check Valves Only the above package content, other products are not included. Note: Light reflection 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.