38 mm Screw Cap with Hole

It does the job.

I works just fine, but unfortunately it breaks easily so be careful not to push the air lock down too much. Great customer service I got a replacement immediately!!

Good Cap, But Fragile

These caps work as advertised, but they tend to crack. Definitely buy extras.

Perfect fit!

Ordered to replace a cracked screen cap for my 1 gal carboy. Fits perfectly with both airlock and jar mouth and it's not cracked (SUPER BONUS!). Mine hasn't cracked yet, but it's currently on its first use. I did order a backup and a rubber stopper just in case.