De TWSBI Eco is made of transparent plastic, which provides a wonderful view on the inside of the pen, the cap and piston mechanism are made of orange plastic. The pen’s character will change with every other color you fill it with.
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.