GTIN #00850007805517 ✔️ Much More Durable Plastic: Compared with other three-piece airlocks, it is stronger, less breakage, transparent, and made of food-grade materials. You can easily see the entire fermentation process, they can last for a long time, because they are the best choice airlock! ✔️ Multi-functional use: The air lock can be used for various fermentation projects to preserve food. As a brewing airlock, craft beer, wine, sauerkraut, kimchi, cider, fruit wine, rice wine, broccoli, carrot, ginger, and other fermented items that are brewed. ✔️ Good air tightness: The good air tightness of the fermentation airlock makes fermentation easier, effectively isolates the air and prevents oxidation. Automatic exhaust at room temperature without manual control. ✔️ Package content: 4 fermentation airlocks, size: height 4.5in/11.5cm. The quality is good and the price is right. ✔️ Brewing America Guarantee: If you are not satisfied or if you have any questions, please contact u