Confusing Element in back side of nothing ear 3 case

Hi ,

There is a small Grill showing in the back side of nothing ear 3 case.

I have tried to understanding regarding this but no idea. Anyone knows about this . How its work?🤔🤔🤔

KVJaibin it helps the supermic

JochieSantiago oh ok .thank you dear.

And actually how it does working,i mean for what purpose this implemented.

KVJaibin it is the mic