Materials: These airlock stoppers are made of food-grade PP plastic, and it is transparent, allowing you to determine when to stop fermentationwine fermentation airlock wine fermentation kit wine airlock stopper fermentation brewing airlock twin bubble airlock Function: Used in conjunction with a perforated rubber stopper or silica gel stopper,wine fermentation airlock can effectively isolate the air during the secondary fermentation for red wine fermentation, and at the same time emit carbon dioxide Principle: The single valve twin bubble airlock uses the principle of water seal, which can effectively isolate the oxidation of the fermentation medium by outside air Widely used: The s-shape air lock is very suitable for home brewing of white grapes, red wine, etc Features: The air brake of fermentation brewing airlock is unidirectional and has an S-shaped design, which is easy to use