Theballpoint refillperforms in temperaturesbelow zero to extreme heat, underwater, in zero gravity and at any angle - even upside down!Therefillsare hermetically sealed, pressurised with nitrogen gas, and feature a tungsten carbide ballpoint tip. This design works perfectly with Fisher ink, which is more of a gel than a liquid, with a consistency similar to that of toothpaste. It is only when pressure is applied to the ballpoint that the ink takes on the spreadable properties of a liquid, while still retaining the stickiness needed to adhere to nearly any material.

Black ink withmedium tip (1.1mm).