Fisher space pens are true American originals.
Designed in the heat of the Space Race to work under extreme conditions, they show their true NASA heritage. Every Fisher ballpen has a state-of-the-art refill. All ordinary refills have water-based ink, with a small opening in the top to let in atmospheric pressure. The hole in the top limits the life of the refill to about two years, and this is usually why the refill stops, not because it runs out of ink. The Fisher refill is totally sealed, giving it a refill life of 100 years. It will last as long as there is ink in it.
The refill is charged with 50 psi (350 kPa) nitrogen, which forces a small ball down on top of the ink column towards the ball nib. The ink is based on a synthetic rubber, so it is dense and sticky, allowing it to write on wet and greasy surfaces, but it comes out easily because of the gas pressure.
What does all of this mean, assuming you are not an astronaut in space, climber on Mt Everest or in the Military, all places these pens are used? You get a ballpen which is a delight to write with a dense bold line with a minimum of effort, and which always works.
