I don't care whether a pen will work in the weightless vacuum of outer space, or at 300 degrees, or standing on my head at the bottom of the Marianas Trench. I don't care because if I find myself in those conditions I have more to worry about than whether my pen works.

However, I do care quite a lot whether a pen works outdoors at 30 to 40 degrees f. Such conditions, if you have to work out in them all day, only make you WISH you could die. While I'm out there in the cold I need something to write with, and a standard ballpoint won't do it. The ball locks up in cold temperatures. It will tear a hole in the paper before it will leave a mark.

The Fisher Space Pen does work in the cold, which is why I always carry one. I thought the Tombow Airpress might be a good substitute for the Fisher. Not a chance. It freezes up in moderate cold just like a standard ballpoint does.

It also writes like a standard fine ballpoint pen; scratchy weak line, but perfectly adequate for utility grade work. Provided it's warm enough, of course.

Other than that, the pen is short yet fat, an uncomfortable shape. On one side is a clip that digs unpleasantly into the web of my hand if I hold the pen that way, on the other a lanyard loop molded in which does the same, so there is no really comfortable way to hold it. It uses a short refill that doesn't contain much ink, so I don't expect it to last too long.

This pen is OK for utility writing under mild weather conditions, but for me it offers no advantages over disposable stick pens that cost much less and contain a larger ink supply.

Great pen. Writes very smoothly and is comfortable in the hand. I think I know why the one reviewer says that the pen leaks at the tip -- if you are one of those folks who fidgit by clicking their pen open and closed alot while thinking about what to write next, you are probably activating the air pressure mechanism and eventually ink will build up on the tip and smear on the page.

I ordered this pen to join my Uni PowerTank to use at my job which requires outside work in all weather. Compared to the Power Tank this one seems to write a tad darker. I think this is because the pressure that remains in the ink cartridge is topped off when you click the pen to use it again. This probably results in more pressure than the constant pressure of the Power Tank. I get a glob of ink on the tip once in a while, but I've trained myself to not click this pen. The pen body is easy to hold onto. I can't recommend it though over the PowerTank other than on aesthetics. It costs much more and does practically the same as the PowerTank.

Amazing pen! Recommended by penaddict.com, bought it for my parents to use on their trip to Uganda to do some journaling and it worked spectacularly! They used it daily for a full month in the middle of the wilds of Africa while they helped build an solar powered potable water system for a remote village. No dust or dirt made it skip a beat. The only thing I could complain about is the refills are a little small as with light daily use it only lasted 28 days before it ran dry. I'm ordering a few refills soon.

It is a little odd looking but is a solid performer. The ‘fatness’ of it is helpful with gloved hands.