Size: 84mmMaterial: silicone + steel ring4 pieces (green + red + purple + blue) + 4 pieces steel ring8 pieces (2 * green + 2 * red + 2 * purple + 2 * blue) + 8 pieces steel ringPackage content: 4 pieces cover + 4 pieces steel ring or 8 pieces cover + 8 pieces steel ring1. Waterless fermentation airlock --- The top of the lid has a stop that allows the gas to vent automatically and stop the entry of oxygen, so that no explosion of the container or bent lid are caused. so you don't have to belch every day to relieve the overpressure and maintain the water level.2. lid --- diameter of 84mm. This lid is also suitable for cup cans & which have large mason jars with a wide mouth.3. EASY TO CLEAN --- Flexible silicone lids enable quick and efficient cleaning both in the dishwasher and by hand.4. Food quality proofing lid --- The products are made of 100% food-safe silicone and are BPA-free, odorless and durable.5. Easy to use for beginners or lovers --- An entertaining DIY fermentation canning tool for the production of sauerkraut, kimchi, cucumber or fermented probiotic vegetables.6. Thin design --- Our waterless pipe system consists of a flat lid, which makes storage easier. Our valve design with silicone airlocks takes up less space and allows you to conveniently store your fermenting vegetables in cupboards and drawers.