De TWSBI Vac Mini is made of transparent plastic, which provides a wonderful view on the inside of the pen, the vacuum mechanism and ink level.
The pen’s character will change with every other color you fill it with.
The Vacuum filling mechanism requires you to pull back the knob, to create the vacuum and, with the nib dipped in fountain pen ink, push it back in to fill it with ink. The end will close off the ink reservoir, which makes it very suitable to travel by plane.
For the adventurous people, the pen is easy to take apart for servicing or cleaning. A key and silicone grease are provided with the pen. Do this on your own risk.
TWSBI has been manufacturing pen parts form many companies and decided to use the gained experience by producing it’s own pens under the TWSBI brand.