This fermentation kit features improved threaded lids that are sturdy, durable, and rust-free. When the grommet is inserted, the lids provide an airtight and leakproof seal, eliminating the need to transfer contents or replace the lid after fermentation. The 1-gallon capacity of the mason jars makes them suitable for small-batch homemade brewing, including fruit wine, beer, mead, cider, lemonade, and kombucha. They also function well as storage containers for food, vegetables, and pickled eggs. With a 4.3-inch wide mouth design, the jars offer convenience when adding or removing food, and the opening is large enough to allow for easy hand washing. Made of clear glass with scale marks, the jars let you clearly observe the fermentation process and check if the food has deteriorated. The kit includes 2 carboys (10.5 inches in height and 6.2 inches in width) with lids, 3 airlocks, 2 spare silicone gaskets, 2 spare grommets, 2 chalkboards, and 1 pen, all coming in a safety package. The canning jars are crafted from durable thick glass, are leak-free and BPA-free, reusable, and easy to clean-they're even dishwasher safe. Beyond fermentation, they can serve as glass storage jars for flour, pasta, oats, coffee beans, sugar, rice, and other dry foods. For anti-crack care, it's recommended to soak the jars with airtight lids in warm water before adding boiled water. Avoid sudden temperature changes, such as pouring boiled water into a cold jar without a warm-up process.