Not only are these pens great for the outdoors thanks to their reliability in virtually any condition, but they are also great for air travel (no more worrying about leaking pens).
Simple and reliable, this particular model is also cost efficient.
From the www.spacepen.com website:
Here’s a little history about the Fisher Space Pen Company. 
In the 1950’s there were dozens of ballpoint models, and nearly every one took a different cartridge. In 1953 Paul Fisher invented the “Universal Refill” which could be used in most pens. It was a good seller, since stationery store owners could reduce their stock of assorted refills.
Not content, Paul continued to work on making a better refill. After much experimentation he perfected a refill using thixotropic ink-semisolid until the shearing action of the rolling ball liquefied it-that would flow only when needed. The cartridge was pressurized with nitrogen so that it didn’t rely on gravity to make it work. It was dependable in freezing cold and desert heat. It could also write underwater and upside down. The trick was to have the ink flow when you wanted it to, and not to flow the rest of the time, a problem Fisher solved. Fisher’s development couldn’t have come at a more opportune time. The space race was on, and the astronauts involved in the Mercury and Gemini missions had been using pencils to take notes in space since standard ball points did not work in zero gravity. The Fisher cartridge did work in the weightlessness of outer space and the astronauts, beginning with the October, 1968 Apollo 7 mission began using the Fisher AG-7 Space Pen and cartridge developed in 1966.
1965 – Patent # 3,285,228: Anti-Gravity Pen The original AG7 Anti-Gravity pen was developed by Paul Fisher
1968 – Fisher Space pens used on Apollo 7 after two years of testing by NASA
1976 – The Fisher Space Pen Co moves into its 30,000 square foot manufacturing facility in Boulder City, Nevada from Van Nuys, California.
1980 – Paul Fisher was selected Small Business Person of the Year for the State of Nevada1983 – Fisher Space Pen is used by Ronald Reagan to sign the Proclamation inaugurating the Air and Space Bicentennial Year to celebrate Man’s first flight in a hot air balloon near Paris France
1985 – Fisher Space Pen Co. produces the Stowaway pen line manufactured using genuine gold from the treasure recovered from the 1622 Spanish Galleon – Nuestra Señora de Atocha
1995-96 – Fisher Space Pen Co. received the Nevada Governor’s Industrial Appreciation Award as Exporter of the Year
1996 – Good Morning America names the Fisher Space Pen a best stocking stuffer
1996 – Fisher licensed to produce 150th Anniversary Pens for the Smithsonian
1997 – Used during Everest North Face Ski Expedition
– Associated Press released a national article on the Fisher Space Pen Co.
1998 – The Fisher Space Pen is used on the Russian Space Station Mir to write the letters QVV (QVC Shopping Network) – the first product sold in space
– Seinfeld builds an episode around the Fisher Space Pen – Seinfeld is berated by his parents for accepting the pen as a gift from a neighbor who offers it as a token of friendship.
2006 – Sadly, Paul Fisher passed away at the age of 93. The company continues under the leadership of his son, Cary Fisher and almost 100 seasoned employees, many who have been with the company for many decades.
If you’re passing by Boulder City Nevada, stop into the factory store. Open 8am-4pm weekdays.Copyright © 1999 – 2008 Fisher Space Pen Co. All rights reserved.
Style: Cap Activation 
Length: 5.375″
Cartridge: Fisher PR4 Black Ink Medium Point
Barrel Colors: Red, Blue, Green, Yellow, Burgundy, and Black
Packaging: Blister Card
Cost: Around CDN $12
