The TWSBI (commonly pronounced "twiz-bee") Vac Mini is the smaller sibling of the Vac700R. The compact design allows for the cap to be posted on the back of the pen while writing. Like the Vac700R, the TWSBI Mini has a vacuum-filing system and can be disassembled using the included wrench.
To prevent any unseemly burping or leaking due to air pressure or heat changes in the environment, the shut-off valve keeps ink inside the clear barrel reservoir instead of on your hands. For long writing sessions with consistent ink flow, open up the valve to allow more ink to access the feed. The stainless steel nib writes smoothly without interruption.
Unlike other vacuum-filling pens, the Vac Mini is meant to be completely taken apart for thorough cleaning. A special wrench and silicone grease are included to aid in the maintenance of the pen.