Product Details CLEVER DESIGN: These premium quality self burping ferment caps have a one way waterless valve to vent gas automatically while home fermenting vegetables. This simple one-piece airlock requires no water, burping or maintenance. GREAT FOR BEGINNERS: Make healthy home food fermentation simply and easy, perfect for beginners and pros alike. You don't need to buy additional mason lids or oxygen pump. WIDE USAGES: Ferment your own sauerkraut, pickles, kimchi & more. Kimchi jar can ferment any vegetable from cabbage to carrots, cucumbers, tomatoes, garlic, radishes & more. Get your probiotics economically & naturally at home! DISHWASHER SAFE: Our Fermentation Lids are made of high quality silicone, which are tough and durable and easy to clean. They can go into your dishwasher along with your wide mouth mason jars. Food-grade Material: Our silicone fermentation lids are made from high-quality food-grade silicone, completely free from harmful substances like BPA. The premium material ensures that it will not easy to wear, fade or deform. Please Note: These fermentation lids only fit for wide mouth mason jar.