Have you ever hear of a Russian KGB disappearing ink spy pen? The ink is based on a secret formula
developed by KGB scientists during the Cold War period, and more recently adapted into a modern gel pen format.
Despite its unique capabilities, this pen looks and writes exactly like a regular pen and
writes in a standard dark black ink. Since it's a gel pen, it writes smoothly with a
continuous flow, and has a long shelf life. It has a popular 0.5mm point size.
It requires almost no downward pressure to write on the paper, so it's not necessary
to leave indentations on the paper that could possibly be used to reconstruct what was
written.
Once on paper, the ink appears completely after about 20 minutes. Then it begins to slowly
deconstruct.
WARNING: Do not use on any legal document or financial instrument.