Our basic build ozone generators are fully functional ozone generators with a fan, no casing.  Ozone shock treatments are performed in unoccupied aras, and ozone machines collect toxic "junk" inside, so not having a cover is not only no big deal, but a plus. This ozone machine creats 3600 mg/h from one 4KV transformer and one plate.  For shock treatments in rooms up to 400 sq ft.