I remixed my own rod holder. The adhesive wasn't strong enough to keep the rod holders attached to my filament box so I added triangles.

USE:

• print two of these
• cut a length of PVC pipe that is approximately 6mm (1/4") shorter than the width of the box that filament is stored in
• use an adhesive to adhere the spool holder to the walls of the filament box
• thread spools on pvc
• rest pvc on the holder