The Bother of Breather Tubes

They're not much of a bother actually, unless you lose it. In fact, they're quite helpful. Piston-fillers and pump fillers often don't fill completely because the air gets stuck and cannot be expelled without expelling ink. Breather tubes allow a pen to hold more ink because the tube lets the air that's stuck at the end of the reservoir to be expelled instead of the ink that's already in the reservoir. The Parker Vacumatic can be filled by pumping the filler through a few cycles.