Parker Duofold Geometric

In 1939, Parker released a second-tier pen that used the Duofold name. This button filler was called the “Duofold Geometric”, but it was nicknamed “The Toothbrush” for obvious reasons.

Similar to the Penol “Aëro” pens, this was a button filler with a latex ink sac, but with a transparent ink window, as can be seen in the photo above. One funny thing about this pen is that the breather tube (also visible in the photo above) is a fake, since it’s not needed with a button filler. It’s seated into the top of the feeder, but there is no hole connecting it to the outside world. It’s also just long enough to be visible through the ink window, since it doesn’t need to be any longer than this.

By 1940, the Duofold Geometric was replaced by the Striped Duofold like this one.