This Super Fermentation Lid with Airlock features an upgraded threaded design that’s sturdy, durable, and rust-proof. With a grommet for airtight and leakproof sealing, it eliminates the need to transfer contents to another container or lid during fermentation, offering hassle-free convenience. The 1 gal. large-capacity mason jars are perfect for small-batch homemade brewing of fruit wine, beer, mead, cider, lemonade, kombucha, and more, while also serving as ideal containers for storing food, vegetables, and pickled eggs. The 4.3 in. wide mouth design ensures easy access for adding/removing ingredients and hand-washing, while the clear glass with scale marks allows you to monitor the fermentation process and check for spoilage at a glance. The fermentation kit includes 2 glass carboys (10.5 in. H x 6.2 in. W) with lids, 3 airlocks, 2 spare silicone gaskets, 2 spare grommets, 2 chalkboards, 1 pen, and comes in secure packaging for worry-free shipping. Crafted from thick, durable glass that’s BPA-free, leakproof, and dishwasher-safe, these jars are reusable and easy to clean. Beyond fermentation, they double as storage jars for dry foods like flour, pasta, oats, coffee beans, sugar, rice, and more. For anti-crack protection, always soak the jars with lids in warm water before adding boiling water, and avoid sudden temperature changes (e.g., pouring boiling water into a cold jar or placing a hot jar on a cool/wet surface) to extend their lifespan.