Fennecs like to bask in the sun, explore new heights, and dash around.  Observe your fennec's behavior.. some fennecs prefer more lateral movement, so you'll need an enclosure with length.  Some fennecs are leapers! These guys will need an enclosure that's tall with levels to jump on.  Some fennecs are climbers, for which mesh enclosures make sense. Whatever you choose, make sure the openings close securely because fennecs are smart and will figure out how to open zippers, squeeze past bungee fastenings, or chew through cloth.