The original Bullet Space Pen was conceived in July of 1948. Paul Fisher was soon machining a new pen design shaped from solid aluminum. It became the first Fisher ball point pen the #400 Bullet Pen is arguably the most popular pen of the twentieth century. This pen is now all brass with a Matte black finish.When closed the Bullet Space Pen is the perfect size to carry in your wallet pocket purse car glove box organizer or toolbox. When open it s a full sized evenly balanced writing instrument. The patented ink cartridge was designed by Paul Fisher for NASA in the 1960 s enabling it to write in temperatures from -30 to +250 degrees Fahrenheit under water in zero gravity at any angle even upside down. Includes removable clip.