Travel Makeup Bag, Fermenter Lid Grommet,Silicone Grommets For Mason Jars/Airlock/Straws/Plastic Bucket Fermenter Lids,5/8" OD & 3/8" ID (fermenter grommet)

They are rubber grommets it’s hard for me to imagine what you would need to know in a review about them. Their mouth can fit a pencil tightly.

i had to look online for the right size to drill for the hole. I think that should be as least included on the bag. otherwise it went in great.

Did not get all the airlocks. I was shortened by 2.

Great for what they are. Knocked a star off because there's no provided instructions on how big a hole to drill for them. Ruined a lid to trial and error before I got it right.

My husband stamped holes in my wide mouth canning lids, and the grommets slipped right in. I will be using these for fermenting valves.

I used these as gaskets on lids/caps that I drilled holes to insert airlocks into. They work great. Malleable enough to fit around hole and airlocks fit snug inside them for no air leaks.

Did the job sealing my bubblers quite nicely. Seems well made and durable.

As long as you're careful with the drilling the grommets are airtight and very consistent with the shape

Exactly what I expected