What do you call it?

99 44/100% of the time, those separators are protected from the elements inside the housing behind the outer lens, so they do not get damaged like they would if they were out in the open, so they are often times in good usable shape.

In the 14 years that I've worked here at Layson's, we have never had a request for us to find those......

With that being said, it'd be hard to justify the tooling costs to produce them.