Silicone Fermentation Air Lock Stretch Lids PATENT PENDING FERMENTATION STRETCH LIDS - Just one single piece, each silicone stretch airlock lid immediately turns any wide mouth mason jar into a vegetable fermenter SET IT AND FORGET IT - Our self-burping silicone fermentation stretch lids are designed to grip the top of any standard-sized wide mouth mason jar creating an air-tight seal. Simultaneously, each lid is equipped with a one-way pressure release valve; this waterless airlock allows built-up carbon dioxide gas to escape during fermentation without allowing oxygen into your fermenter HOMEMADE PROBIOTIC-RICH FOOD MADE EASY: Fermentation stretch lids are perfect for all DIY fermentation needs. Make your own pickles, sauerkraut, ginger, pickled eggs, kimchi, vinegar, hot sauce & more. Get creative!