I can also vouch for the fisher space pen, I know for a fact they will write upside down,underwater and in space and I have left them in my car for sometime and they always wrote. I had went down to office depo and bought a cross pen and put a fisher space pen refill in it of med black and that was what I used at work. Our company put a strong emphasis on these pens and that's how I got into them. Also we had a Sharpie got left in one of the shuttles years back and when it came home, it still wrote. Totally blew my mind with the Temperatures in the back plus the vacuum back there you would think it would dry it out. Anyhow if you take that pen and fill up a glass of water and put some cardboard at the bottom, try writing on the paper. It doesn't skip a beat. I would definitely recommend there cartage's whether you buy the whole pen or a different pen and use there cartage.