This is a 1" piece of circular cutaway molding for finishing a wall. The trim is approximately 10.6" long, and has mounting holes for a #1 wire brad.
For additional dimensions see the attached picture. NOTE: Those dimensions are in milimeters.
I would not suggest printing this part in PETG as having paint stick to PETG would be difficult.
I would use PLA or ABS.
1.) Optional - Spray with automotive filler primer, sand when dry.
2.) Cut part to length
3.) Using No. 1 brads nail molding into wall using corresponding thru holes located on the part.
Please reach out for native, or STEP file formats.