Enclosures can get pretty big, and sometimes there's not a lot of space in back to fit between the table and the wall. In those cases, you can 3D print your own extender to move the filter to the side.
Tyler's 3D Hub came up with the idea and CAD'd this 3D printer carbon filter extender on Thingiverse. When we switched to the 60mm fans with the Prusa we created our own extender that fits that smaller filter.
Note that these only work with the Prusa enclosures.