this is the fan used for moving air round the box
http://i67.photobucket.com/albums/h310/jamiewatling/DSC00437.jpg
this shows the top fan which it the out and the bottom it the in
http://i67.photobucket.com/albums/h310/jamiewatling/DSC00438.jpg
this is where the out exits, it a getto muffler...