I found keeping a hygrometer in the jar was sometimes a pain in the ass, but I just want to say these lids are nice. $8 for 4 on etsy.com by Engineered Essentials. They are made for wide-mouthed Mason/Ball jars. They come with a silicone gasket an you can get them with, or without hygrometers.
Just thought I would pass them on, incase it's something someone else may find useful.
Just thought I would pass them on, incase it's something someone else may find useful.