Traveler's pen

Made of gel-based rollerball pen. I've cut half-empty ink reservoir to fit the bottom part. The cap from the same "donor" - Pilot gel-based rollerball pen. The bottom part can be stored in the top part. Fits at least in my wallet (a little bit thick..) but greate for filling immigration cards when you are traveling. Quite comfortable to use (since it's a full-size pen).
Tested only on 1 pen, so maybe it needs some adjustments (write about it in the comments, I will try to alter the models).
V