Hi, Folks and congratulations, Greenie!
The Wahl-Eversharp Pacemaker was advertised in 1939 in several publications and has design cues from the top of the line Coronet, such as the clip. These five inch long pens are notable for their intense striped celluloids, extra trim, and pointed cap and barrel ends. They are lever fillers with ink-view window sections and 14 karat gold nibs in many grades including this flexible one.
It was priced below the Doric at $3.50 for the pen and $3.00 for the matching repeater pencil, but was offered as set for $5.00. The pen came in two sizes, shown here, differing only in width. Pacemakers were first offered in black, green or gold satin pyralin. Blue was added later in 1939 followed by red, for a total of five color choices.
Now that you know there are two sizes, you have some more work to do!