6) Vacumatic, Parker 1933 back This system as well uses a pen sac, but the reservoir itself is the barrel. The sac is mounted at the barrelīs end. When pushed into the barrel with a rod or a longer know, the inside volume is reduced, air is pressed out of the barrel. The low vaccuum, built up, when the rubber sac snpas back into position, draws ink though a small tube. Pressed six or seven times, this system drwas an enormous volume of ink, as the complete barrel can be used as a reservoir.