The military takes their pens seriously. In fact, they are labeled as “skill craft” for technical purposes and consist of seven unique parts. They also must pass certain qualifications set forth by a 16-page military spec manual. A couple of the most interesting is a pen must be able to write for at least a mile with no fading. It must also be able to operate within a temperature range of -40° to 160° Fahrenheit. Interestingly enough, this regulation can be traced back to the Great Depression.