Parker Duofold Senior
This NOS (New, Old Stock) Duofold Senior was made in 1925 (the date can be established by the fact that it has a single flush cap band or ‘girdle’ as Parker called it back then, in addition to the imprint on the nib).
Included in the box were the original American instructions as well as a Danish translation, which would indicate that this pen was imported to Denmark by the Chr. Olsen company before the “CO” imprint was added to the Danish imports, a practice that started in the late 1920s.
It might be interesting to note that the first page of the instructions (below) show a drawing of a Duofold with a tapered cap and two bands, a design that was released in 1929.
There is a document available here that describes the advertising and marketing of this pen.