This ink set was designed in 1917 by Hoffmann's student and then co-worker at Wiener Werkstätte, Carl Witzmann, as an appreciation for his master/teacher.
After Witzmann had left Wiener Werkstätte, Hoffmann probably had his designer's monogram engraved on the second writing set.
Sincere thanks to Mr. H.S. for this information ODER: for the professional categorization of this object.
Cat. No. M23/64