Cooling fan for dual extruder

Just finished to design it in order to fit with the excellent dual extruder done by Riku Rusanen : http://www.thingiverse.com/thing:201184
The thickness of the duct has been resized to 1.5 mm in order to ease the building of the walls. Overweight should be unimportant.
IMPORTANT ! choose the fan duct related to the extruder you' ll use to print that duct:
_ fan duct 1.4 to be printed with 0.4 extruder
_Fan duct 1.5 to be printed with 0.5 extruder
Prévu pour l' excellent extrudeur