My pen is one of my most used EDC items. The pen that I have carried for the last 3 years is the Inka Pen. It is light weight, very compact, extremely durable, it writes well, and it is just down right cool.
The Inka Pen has three modes of use: a closed mode for carry, a compact mode for quick notes, and a full sized pen mode for extended writing. These three modes are part of what makes the Inka Pen such a joy to use and carry. It rides unobtrusively on your key chain until it is needed. If you need to jot down a quick note you can quickly pull the plastic end from the metal tube for a compact writing instrument. If you are going to be writing more, you can assemble the Inka Pen into a full size pen that writes very well.
The Inka Pen uses a pressurized ink cartridge that allows it to write in any condition, much like a Fisher Space Pen. I am not a pen connoisseur, but this cartridge seems to write very well and has lasted me all 3 years that I have owned the pen.
This pen is so functional and convenient that I don’t think I will ever carry a full sized pen again.