Fisher Pressurized Ballpoint Pen Refill - Medium Point, Black Ink - Perfect for Office, School & Everyday Writing Needs

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 medium tip (1.1mm).