This is an adapter for a 2015-2020 F-150 front and rear door speakers to go from the OEM size to 6.5" drivers.
Recommended print in PETG. I printed mine at 235c/70c @60mm/s
Predrilled holes are lined up for Rockford Fosgate speakers, but I am including STEP files so people can adjust them to fit other speakers.
The author hasn't provided the model origin yet.