High Quality Materials- Made of food grade plastic with a cap. Advantage- This fermentation tube allows fermentation gas to escape while excluding air and contaminants. The transparent airlock lets you know exactly when the fermentation is slowing down and eventually stopping the fermentation. Easy to Use - Just pour water into the airlock, insert it into the lid from the brew tank or into the rubber stopper above the fermentation vessel, then cover it. Exterior- S-shaped design, connected by a trap, prevents the oxygen from entering your fermenter. The whole fermentation process is automatic fermentation, without manual control, and can be reused for a long time. Usage- It can be used for pure juice fermentation, mead , white wine, milk alcohol fermentation, red wine secondary fermentation, etc. Due to factors such as manual measurement and display differences, there may be some slight differences between individual products and images, please excuse me.