Answered! The search term is "earphone port hole patch"

I'm on the hunt for a particular item to use in my insulin pump pouch sewing project...

It's like a cord pass-through for headphones but slightly bigger. I imagine it's made of silicone. In this backpack image, it'd be the little silicone slit on the first pouch from the body of the backpack to give an example of what I'm looking for.

Any ideas what I might be looking for? Thanks!

(Edit: It does not have to be a single slit, it could be a star passthrough, or anything that can be large enough to put a large coin through.)

#sewing @sewing