Fisher Space Pen Ballpoint Pen, Matte Black Navy Insignia (M4BNAV) Officially licensed by the U.S. Navy. This Matte Black Cap-O-Matic Space Pen, withwith Laser Engraved US Navy Insignia. Writes upside down - at any angle, under water, through grease, in extreme temperatures (-30 to +250 degrees F), on almost any surface, three times longer than the average pen. Our refills are hermetically sealed, pressurized with nitrogen gas, and feature a tungsten carbide ballpoint tip - the same extra hard metal that is used to make armor-piercing ammunition. The Fisher Space Pen is precision assembled in the USA, hand tested, and carries a lifetime guarantee against all manufacturing defects. Overall Length: 5.375"