Features:1. Automatic Air Valve Design: The gas generated during fermentation can be automatically discharged, effectively avoiding extreme situations such as tank expansion.2. Time Recorder: There is a time recorder on the lid, to keep track of batches, No more needing to remember when that batch started.3. Minimizes Chances of Rot: Silicone double seal, no air leakage, no water leakage, it is very hard for contaminates to grow in a vacuum, increasing your chances for success. Extend the freshness and shelf life of things4. Safe Glass Material: The glass fermentation jar is made with healthy glass, a perfect choice for storage and fermenting food, to ensure the best environment for fermenting vegetables, no dust or chemicals leach into the food anymore.5. Applicable: Perfect for fermenting sauerkraut, wine, fruit, and any other fermented vegetables or foodstuffs you might fancy, easy to use, and easy to clean. Specification:Material: Glass Color: Blue Capacity: 500ml, 750ml, 1000ml, 1500ml Product Size: 10.7 x 11cm, 14.2 x 11cm, 17.2 x 11cm, 22 x 11.5cmProduct Weight: 550g, 650g, 800g, 900gPackage Included:1 x Fermentation Jar