prusa i3 rework 50mm print fan duct (mount holder)

A remix of http://www.thingiverse.com/thing:431506 but is for 50mm fan (distance between holes of 40mm) and has a shape a little different.
i use it on prusa i3 rework with j-head
to mount in a good position the fan with the e3d hot end http://www.thingiverse.com/thing:953807

http://sallyengineering.weebly.com/