This is a trim clip for the silver/chrome trim that runs the length of the car.

Originally printed for my 1964 dodge dart gt. The clips slide into the rails and press into the holes on the body. They are robust and even reusable, a few times anyway. I usually print 50 at a time out of PETG and and 0.2 mm nozzle (Super quality on Cura) - this gets me a sturdy clip that still slides in the rails.