cooling fan + duct dual extruder

--------------------- EDIT -----------------------
The last STL provided does not match with the photos .
The lower part has been redone in oder to adjust the air flow at the tip of the hot end.
The separation between the 2 nozzles has been deleted.
Solidwork file attached accordingly.

designed for the excellent dual extruder from Riku Rusanen http://www.thingiverse.com/thing:201184.
The design has been done for the 20.50 mm spacing ( the closest one ).
The square holes are provided to secure the installation with a zip tie around the cold part of the extruder.
Solidwork file provided for mods. Enjoy and let me know ;-)