What are these fuzzy window guide things?

Thanks TrailBeast.

I'm wrestling with the notion of replacing these things or monkeying with the door sweeps at all until I figure everything out, but that info helps. On one hand, the only time the car sees water is when I wash it which is quite often but while it's all ripped apart... (If it ain't broke.?..)......

Indecision is the key to flexibility :-(