READ: The Ultimate TWSBI guide before buying.

With a piston filling mechanism, a clear demonstrator body, and included tools for long-term maintenance, the TWSBI Eco is a wonderful value at a low price.

Due to the piston-fill mechanism, this pen is able to hold a large volume of ink. The package includes a wrench and silicone grease intended for long-term maintenance, and the clear body allows you to see all the inner mechanisms of the pen as they work. The TWSBI Eco is a great option for those who want to really understand the inner workings of their pen!