The TWSBI Eco-T Fountain Pen features a clear 'demonstrator' barrel that showcases the internal piston-filling mechanism. Its Eco-T variant offers a more triangular grip area and a matching triangular cap, designed for users who prefer a tailored hold. The pen is accented with chromed metal trim and a pocket clip, with the TWSBI logo on the cap top. A rubber o-ring on the cap thread ensures an airtight seal, preventing ink from drying and keeping the cap securely attached. The faceted cap prevents the pen from rolling off surfaces. It is equipped with a polished steel nib, available in extra-fine, fine, medium, broad, and stub sizes, all engraved with the TWSBI logo and branding. Please note that piston-filler pens are not compatible with cartridges. The pen is supplied in gift packaging and, like all TWSBI fountain pens, can be fully disassembled for cleaning and servicing. Instructions and tools are included, though disassembly is recommended for experienced users and not required for normal operation. Disassembly is undertaken at the owner's risk.