Blue Ink Fine Point Space Pen Pressurized Cartridge. Fits in any space pen.
Paul Fisher started the Fisher Pen Company in 1948. His first noteworthy invention was a universal refill cartridge, the second was a pressurized and sealed cartridge. The pressure allowed the pen to evenly distribute ink underwater, upside down, over grease, in extreme temperatures and in zero gravity. Twenty years after the company was founded, the AG7 Fisher Space Pen was used on the Apollo 7 mission after 18 months of testing by NASA. Fisher is a small, family run company. 65 employees continue to make high quality pens in Boulder City, Nevada.