Fisher space Model 400CZN Bullet Space Pen. What a clean crisp new look! The cap is plated with Copper Zirconium Nitride. If you want the newest and the sharpest, this is the Bullet Space Pen for you! When closed, Cartridge Space Pens are 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 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 our first Fisher ball point pen, the 400 Bullet Pen, and arguably the most popular pen of the twentieth century.Cited as an outstanding example of industrial art, the classic design of the Fisher Bullet Pen has been exhibited for years in the New York Museum of Modern Art. The Bullet's timeless styling has been the topic of many art books and magazine articles. Often imitated but never duplicated, the Fisher Bullet continues to be our most popular pen.