TWSBI Eco Cosmos with Onyx fountain pen

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 blue green swirl color plastic with black nib and clip. The pen’s character will change with every other ink color you fill it with.
The pen is easy to take apart for servicing or cleaning if required. A key and silicone grease are provided with the pen.