Review on Maximize Fermentation with Masontops Pickle Pipes - Waterless Airlock Lids for Wide Mouth Mason Jars - Top Quality Silicone Caps by Jennifer Jackson

Well they are easy to use and not difficult to clean. However, if the liquid/brine is too high above the neck of the vessel, the liquid will be pushed up through the opening as it ferments. It took me a few tries to figure out how to fill the jar just enough to easily remove my jar weights (that's a different product), but not so much that the liquid got into the opening of these lids and overflowed. In addition, ventilation is not automatic. Or maybe I'm just not patient enough. I watch my eyelids and when I see them bulging I squeeze the openings which happens about 2 or 3 times a day. The lids don't seem to let any outside air in (other than the original air that is present when I put the lids on). They are so useful that I still use them to this day, but I found glass weights would work great on their own.