Models
Duct 3D Printable Models. Makeshape.co have 3 Duct 3D Printable Models.
Electric duct junction reducer ICTA (3/4″ to 1/2″) 20mm to 16mm
Thingiverse
Neopicture
Free
E36 Fog light duct – Perfect fit
Thingiverse
J99works
Free
4″(101.6mm) Diameter Inline Duct fan Support
Makerworld
AJ Eng. & Design
Free