The Duo family comprises two sets of shaded capitals: Duo Licht and Duo Dunkel (in English Duo Outline & Duo Solid; in Spanish Duo Clara & Duo Negra). Designed by Alfred Finsterer for Gebr. Klingspor in 1954, the typeface was also cast by D. Stempel AG [Jens Jørgen Hansen].

Dieter Steffmann made a digital freebie version (1999). He also released another version of Duo Dunkel as North Face.