1920s to 1945
The years when fountain pens became everyday tools. Celluloid took over from hard rubber in the mid 1920s, which brought the bright colors and pearly stripes collectors chase, like Parker's Permanite Duofolds and Sheaffer's Radite pens. Button and lever fillers were the norm until Parker's Vacumatic (1933) and Pelikan's piston filler (1929) changed how pens held ink. Pens this old almost always need restoring. Expect a new sac or diaphragm, and check the celluloid for cracks, shrinkage and discoloration.
6 pens we cover.

Parker · 1941–1948
VacumaticVacumatic filler, 1941 to 1948
Pre-war and wartime
$100–$210 typical ask
35 on eBay

Parker · 1937–1948
VacumaticMid-size Vacumatic, 1937 to 1948
Pre-war and wartime
$140–$240 typical ask
25 on eBay

Parker · 1921–1936
Button and lever fillerPermanite flat-top, late 1920s
Pre-war and wartime
$270–$490 typical ask
26 on eBay

Parker · 1937–1948
VacumaticLadies' size Vacumatic, 1937 to 1948
Pre-war and wartime
$200–$290 typical ask
12 on eBay

Sheaffer · 1929–1942
Button and lever fillerStriated Marine Green, lever filler, 1937
Pre-war and wartime
$110–$190 typical ask
36 on eBay

Pelikan · 1929–1944
PistonThe first Pelikan, celluloid barrel
Pre-war and wartime
$400–$550 typical ask
10 on eBay