Parker Vacumatic

Parker boasted the model to be the first self-filler without a sac; while this was not entirely true, the filling mechanism was still a great innovation.

The principal workings are essentially like that of the earlier button fillers like the Duofold as the depression of the plunger pushed on the rubber sac and forced out the air (creating a vacuum) and when the rubber regained its natural form the ink got sucked into the pen to replace the air.

The difference was that the previous button was replaced with a fat (approximately 4 mm) plunger that was used to operate the diaphragm.

The plunger could be locked in a down position with a twist of the thumb and is referred to as the Lock-Down Fill, or Twist-Fill.

Although the pen came in many sizes and colors, the most widely recognizable Vacumatics featured alternating horizontal bands of pearlescent and clear celluloid.