Fisher Pressurized Ballpoint Pen Refill - Black Fine Point Ink Cartridge for Smooth Writing at Home, Office, or School

The  ballpoint refill performs in temperatures below zero to extreme heat, underwater, in zero gravity and at any angle - even upside down! The refills are 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 with fine tip (0.9mm).