Review on Ultimate Leak-Proof Platinum Silicone Sealing Lid Inserts/Liners for Mason Jars - 10 Pack (Wide Mouth) by Lisa Starcher

Simply poke a hole through each of these silicone lid inserts about half an inch from center, screw them to the top of your jars with metal ties, and you've got great airlocks for all your lactic fermentation pickles! They work the same way as Masontops Pickle Pipes, but better and cheaper. Place the hole about half an inch off center, not exactly in the center where the dimpled and thinner silicone is. The orifice acts as a safety valve and only lets air through if the pressure difference between inside and outside is large enough. During fermentation, the liner in the lid bulges upward, indicating that a significant pressure differential is required to force air through the hole. This means the hole won't let air in at small pressure differences, meaning the inserts in the lid can be used as regular mason jars when not fermenting. The bulge also tells you that the pressure inside the can is higher than outside the can, meaning air can only flow from the inside out and nothing gets in. The opening will not increase over time, so the performance of the safety valve is maintained for a long time. The inserts in the lid are perfect for metal bands or plastic ball tops, so they center perfectly on the rim of your jar. They have a groove and rib on the rim that keep them firmly in place and prevent them from coming loose from the rim of the pressure can. They're thick, easy to clean, and not too expensive. Pickle Pipes is worse on all of these counts. Pickling pipes have a safety valve that will loosen over time. They are too small and difficult to center in the glass, so they can come off the rim during fermentation. They have no groove or rib to fix them to the rim of the can. I've been using these lidding liners for pickling vegetables for a week. I've played many games and never had any problems.