Uni-Ball Power Tank Heavy-Duty Ballpoint Pen Retractable 1.0mm Blue

Oil-based ink, expelled from the pen by air compressed to 3000hectopascal to ensure smooth writing performance and a distinct line quality. Pressure forces ink out of the pen, ensuring uninterrupted ink flow even when you are writing quickly. There are no spots or broken lines. Even if you only press lightly, you can achieve smooth and even lines.
Writes smoothly on the wall calendars, and flipcharts. Even when the pen is held in an upward position there is no ink back-flow and the pen continues to write smoothly.
This is an all-weather pen that can be used in any environment, including outer space.