The Wartime/Postwar Filler: In 1942, the United States was at war, and aluminum was declared a critical resource. Parker redesigned the Vacumatic filler to use a plastic plunger. This plunger, made of celluloid, is smaller in diameter than its metal predecessors, with a button end like the cap of a mushroom. Parker used this new filler design unchanged until the Vacumatic model was discontinued.