There are numerous astronauts who have used the Fisher Bullet Space Pen in the great unknown. The Fisher Bullet has been on every American and Russian space mission since the mid-sixties. With its pressurized ink cartridge, the Space Pen writes upside down, under water, through grease and in the zero-gravity vacuum of outer space. Choose your Bullet Space Pen from a wide variety of colors which all engrave beautifully. Order extra pressurized refills, also available in a wide range of colors and point sizes. A pocket clip may be purchased separately.