1. Easiest Mason Jar Fermentation Air Lock: These premium selfopening fermentation lids feature a oneway waterless valve that automatically vents gas when fermenting vegetables at home. This simple onepiece airlock requires no water, burps, or maintenance. 2. Foolproof Fermenting Accessories: Fermenting vegetables can be tricky without the right pickling supplies and equipment. Strong pressure is present and may blow off the lid or even burst the glass. Open air can spoil the fermentation, so our oneway valve prevents spoilage. 3. Right Size & Premium Materials: The fermenter lid is made of premium silicone, easy to clean. They can go into your dishwasher along with your widemouth mason jar. 4. Space Saving: Our silicone airlock valve is designed to take up less space, allowing you to conveniently store fermented vegetables in cupboards and drawers. 5. Make Probiotic Rich Foods At Home: Ferment your own sauerkraut, sauerkraut, sauerkraut, and more. Can ferment any vegetable, from cabbage to carrots, cucumbers, tomatoes, garlic, radishes, and more. Get probiotics economically and naturally at home. Specification: Material: Silicone + PP Color: Blue, Green, Red, Gray, White, Lake Green Product Size: 10 x 10 x 3cm Package Weight: 150g Package Included: 6 x Mason Jar LidsPackage Included: 6 x Mason Jar Lids