The organic silicon fermentation cover is made of food-grade organic silicon, tasteless, no BPA, oxidation decomposition temperature far exceeds similar organic silicon products, does not fade under daily temperature, and has a long service life. The organic silicone fermentation cover can be used for a long time, has no peculiar smell, no BPA, does not fade under daily temperature. Suitable for dishwashers, and can also be easily washed by hand, without time-consuming and labor-intensive maintenance. The fermentation tank lid, 8.6cm / 3.4inches in diameter, suitable for fermenters for making sauerkraut, from cabbage to carrots, cucumbers, tomatoes, garlic, radishes & more, ferment your own sauerkraut, pickles, kimchi & more and can also be used to store coffee beans. Package includes 5 silicone fermenting lids, with or without 5 metal rings, depends on your choice.