FDA High Transparency AirlockDifferent than other normal S shape airlock in the market,it`s made of healthy material,more harder (no fragile)and more transparent.(Clearly see the whole fermentation process)Apply pressure slowing to the airlock when inserting into the drilled plug/stopper and they will last a long time as it`s top quality transparent airlock.Good airtightness The good airtightness of the fermentation airlock makes fermentation easier, effectively isolates the air and prevents oxidation. Automatic exhaust at room temperature without manual control. Easy On & Off Cap -This type of dust cap has a zigzag design on the surface and will not slide when opened. There are 3 buckles inside, press it down gently, you can close it with a snap, pull it up and rotate to open it. The lid does not need to be drilled as there is gap around it, which allows the gas to escape.Reusable & Widely Application These airlocks are solid and reusable.They can lasts for a long time,just drop it in your sanitizer and reuse it many times and many.The air lock can be used for various fermentation projects to preserve food,craft beer, wine, sauerkraut, kimchi, cider, fruit wine, rice wine, broccoli, carrot and ginger, and kimchi are brewed.,occasions(kimchi,kombucha,brewing wine making).Package content 6 fermentation airlocks, size: height 6.7in/17cm. 12 airlock grommets, size: inner ring diameter is 0.39in/1cm, outer ring diameter is 0.59in/1.5cm, the is sufficient, As a spare, the price is right.