This is a model I created to cover the AC Infinity Exhaust Fan when it is not in use.  I have split the model into two halves.  Once printed, glue the halves together.  I used some basic cheap weather stripping on the inside to seal the box around the fan.  It will be tight at first but then it will eventually fit perfectly once the weather stripping adapts to the contour of the fan.  Hope this can help someone the way it helped me!  Thanks for looking and happy printing!