Hi guys, this might sound stupid, but I'm trying to figure out what goes in the door panel, where the armrest is?

Would anybody know what goes in there? And where I can find this part, or for that matter what it's called.

Originally when I bought the car, there were no door panels, so I'm kind of lost what goes there.

https://moparforums.com/forums/membe...3-imag0115.jpg

Thanks

 

A PLAStic insert/cup goes there

 

Any idea where I might buy it?

thanks