10 Food Grade, Silicone Airlock Grommets. These insert into a 1/2″ hole. BPA free.
Use to add an airlock port to a container of your choosing. I know of several grommet offerings, most don’t claim to be food grade. That’s probably not a big deal considering that most of the time this gets little to no contact with your beer. Having said that, it’s nice to have a food grade option.