The skilcraft US government pen, was spec'd to write 5k in -40F to 160F and is also manufactured by the blind. I've got a box of them spread out anywhere I need a pen.
My grandfather had a skillcraft stick pen (the cheapest one they make) from his last job before retiring. I'm pretty sure that same pen sat in a cup in his kitchen for like 30 years and was used daily. Never ran out.
measuring ink capacity in km makes total sense but I find it hilarious