Fermentology Sauer System Mason Jar Fermentation Airlock Lid Kit - Includes Tough Tops Plastic Mason Jar Lids, 3-Piece Airlocks, Silicone Grommets, Gaskets and Stoppers - WIDE MOUTH - 4 PACK ALL-IN-ONE - Complete airlock system releases pressure without allowing oxygen or other contaminants into your ferment. Includes 4 of each of the following: Tough Tops Durable Lid, Supreme Airlock, Silicone Grommet, Silicone Gasket, Silicone Stopper. FITS ANY WIDE MOUTH JAR - Will work with Ball, Kerr, Bernardin. Any brand of "Wide Mouth" Mason jar in pint, quart, or half-gallon. BPA-FREE - All components are certified BPA-Free and custom made for a perfect fit. TOUGH TOPS INCLUDED - The best selling Masontops Tough Top is the lid of choice for this system. Built to last, unlike flimsy "plastic storage caps" that bend and crack. TRUST THE TEAL - Unlike "home made" kits, Fermentology products are all inspected and verified to be high quality, durable, and safe for you and your family. As food ferments, it creates gas that must be released without exposing the ferment to open airoxygen causes mold! The Sauer System uses a 3-piece airlock that releases carbon dioxide, while blocking oxygen with a water barrier The Sauer System is an all-in-one product that includes a Tough Tops Durable Lid, Supreme Airlock, Silicone Grommet, Silicone Gasket and Silicone Stopper The Sauer System is compatible with North Americas most popular jar: the Mason jar All of the parts are easy to assemble and clean, and are made of food safe and BPA-free materials The Sauer System doesnt require any metal, which means no more rusty screw bands! designed to the highest standard of function and durability; tested and certified to be food-safe; and inspected before shipping to ensure it will exceed your expectations.