double barrel duct
thingiverse
I finally got fed up with searching for the perfect solution, so I took matters into my own hands and created one from scratch. This setup requires no additional support as it lies flat. Including this link to troubleshoot or modify if needed on your machine: http://a360.co/2ENuGO9
Download Model from thingiverse
With this file you will be able to print double barrel duct with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on double barrel duct.