Screen for Kellogg Redbar ringer openings

[RotoTech99]

From: RotoTech99

I've noticed Kellogg describes screens that they put over the ringer opening... I believe it is a fabric screen that partly masks the gongs when viewed from the base's bottom....

What is a good substitute for that? I've used old chair bottom fabric with mixed results.

Also, what is a good glue to stick the screen to the base over the ringer opening area?

My reason for asking[is I have two Redbars where the screen is absent, and I'd like to replace it./font]