The Gallon Glass Jar 4PK comes with four Glass Jars, four airtight plastic lids, four rubber bands, and four 12"x12" muslin cloths. Just add the ingredients and you are ready to brew, ferment, store, or decorate whatever your heart desires! <p>Whether you are making kombucha, sun tea, milk or other types of kefir, or storing dry foods, our jar has your back. The seal on the inside of the lid helps preserve what you have put inside. If you are brewing, you can use the muslin cloth to keep bugs and debris out of the jar, while you let the solution breathe.