In 1937 the oversize was replaced with a streamlined version called the Senior Maxima (16 mm Wide, 139 mm Long). This entirely new pen had a wide cap band (app 5 mm) initially with a very attractive engraving with "VACUMATIC" in raised letters on the cap band ; these models are quite rare and of course expensive because they were made during a short períod of time . Later the band was engraved with a pattern of repeated lines leaning left and right: ///\\\///\\\.The unequal banded Senior met with an untimely death and was replaced with the Maxima a more slender version of the Senior Maxima. ( http://www.parkercollector.com/ )
In order to have a look of the whole photo you must click over it.
The Golden brown set and the following emerald green are the slender maxima versions of the Vacumatic. The first set on the left and the two following pens ( brown and burgundy ) are the oversize versions.
I only have the black pencil but not the pen. Parker never made this model in the blue color.