Universal Dual Extruder Printer Fan Duct

I've owned a couple of dual extruding printers and find that the second extruder is more pain than it's worth. Since 99% of prints in the world are single extrusion prints and 50% of those are ruined by an extra extruding head, I always make a point to remove it and replace it with a strategically-placed fan:

https://www.thingiverse.com/thing:1172843

Prints turn out cleaner and life is just better. This new design can be printed in one piece and should work with either a Flashforge Creat