I used ½" EMT Conduit that measured out to be 18mm OD. The conduit was bought from Lowes. 

I used PLA with 3 wall lines and 30% triangle infill 0.4mm nozzle

Lubricate EMT for easier assembly

Included is a file for each bracket for slightly larger holes for slightly larger conduit diameter. If the OD of the conduit measures over 18mm, if your printer produces smaller holes, or if you use a material more prone to shrinkage, use the slightly larger files

LABELS FOUND HERE:

 1/2＂ EMT Filament Labels by PrinterChuck | Download free STL model | Printables.com

All model files can be printed on a 220 x 220 build volume

Printed on a Creality K1C