The Spacetec by Diplomat gas pressurised refill writes even upwards, under water, in blazing heat (up to 200 degrees Celsius), the freezing cold (down to -50 degrees Celcius) and moreover, in the gravity free void. It should write for over three miles before requiring a refill - three times longer than most ballpoint pens.
The Specetec Pocket is the classic "bullet" pen. A slim, all metal casing makes it ideal for use with time planning systems. With the cap on it is a 10cm long pocket pen. With the cap posted, it is a full-lenth 14cm ballpoint that will write anywhere and on almost anything.