This is a upgraded fan duct for the existing fan in a Wanhao duplicator 6 or Monoprice maker ultimate. It is designed to use the existing screws and fan for minimal change.
After looking around a bit I found http://www.thingiverse.com/thing:1826526 which had everything I will be looking for when I eventually do a dual fan setup and included the original 123D file to be able to make modifications. I modified it to remove the second fan and connector pieces. I also noticed that the areas where the screws connect it to the fan were thicker than the original duct so I thinned those out to 2mm so that the original screws could still be used. I left in the back "wall" that wraps around the fan as I found it made it a little easier to attach the duct to the fan and made it feel a little more solid.
I printed this in PLA and it has worked great for me for PLA and woodfill printing with the tip getting up to 210 for the woodfill, however if you are printing in ABS or other materials that require higher heat I would recommend printing this out of a different material as it could potentially melt during printing (The original post recommended PETG). I have not tested the heat limits of this duct beyond 210.
I had supports for anywhere above the print bed, this left the inside of the duct near the tip a bit rough, but it ensured the screw holes printed correctly.