This Pilot Parallel Pen ($(removed)) comes with two ink cartridges (red and blue), but you can a box of 12 cartridges with different colors of ink for $(removed)
Here are some videos of talented people using this pen:
This Pilot Parallel Pen ($(removed)) comes with two ink cartridges (red and blue), but you can a box of 12 cartridges with different colors of ink for $(removed)
Here are some videos of talented people using this pen: