printed in white ABS but PLA or PETG will work just fine

Requires a 1 1/4inch wooden dowel like the one below. Cut to the length required. I cut mine to 2 feet and  stained it with a dark Stain and coated with a Polyurethane coating. Stain not required but I would recommend some sort of protective coating.  

https://www.lowes.com/pd/Madison-Mill-Round-Wood-Poplar-Dowel-Actual-48-in-L-x-1-25-in-dia/3040777 

Printed Parts:

3 walls

10% infill

0.2 mm layer height or use Variable layer height to improve quality 

print two of the screw covers and press them into the hole after screwing into the wall.

feel free to have the dowel holders go up or down