Replace a broken Fiat 500 armrest with a nicely designed little end cap that goes in place. Search YouTube for “Fiat 500 Armrest Removal” for a visual demo of removal, then print this guy, orient it with the wide face of the plug at the base of the print plate.

Print with a Brim or Raft if you have bed adhesion issues.

Recommend Infill 70% (or more)

A round “knob style” include the FIAT type which is removed from the surface by 1.5mm. This one should be easier to print.