With form and function in mind, Fisher Space Pen has created a pen to meet the needs of law enforcement agencies. A four-function pen, the Q-4 incorporates technology for all-weather writing dependability. In extreme temperatures of hot and cold (-20 degrees to 250 degrees Fahrenheit), on rain-soaked paper and at any angle even upside down the Q-4 is guaranteed to write. On demand, the user can choose to write with either red or black ink cartridges. The Q-4 also is ready with a .7mm lead point, and there's an eraser under its cap. The fourth function, a stylus tip, makes the Q-4 PDA ready. Now, officers who use PDAs to issue citations or make scene/incident notes will have to look no further for a stylus than the pen they use for everyday writing. Like all of Fisher's writing instruments, the Q-4 carries an unconditional lifetime guarantee.