TWSBI fountain pen ECO Serpentine with bronze (F)
The TWSBI ECO Serpentine with Bronze is a piston filler made from translucent green acrylic resin, with a pattern created through a special injection molding technique – no two pens look exactly alike. Bronze-colored accents on the clip, cap, and PVD-coated stainless steel nib provide warm contrasts to the cool green tone of the body. The transparent barrel makes the ink level visible at all times and lets you experience the piston mechanism directly as a demonstrator. Available in nib sizes EF, F, M, B, and 1.1 (broad nib).
Special Features
- Serpentine design through injection molding special technique: The green-marbling pattern is created directly in the molding process. Each pen displays individual grain patterns – from deep jade green tones to lighter, almost translucent areas.
- Bronze-colored PVD nib made from stainless steel: The writing nib is PVD-coated in bronze design and engraved with the TWSBI logo. Bronze-coated nibs tend to write slightly broader than silver nibs of the same size designation – particularly relevant for EF and F.
- Integrated piston system with large ink volume: The piston mechanism holds approximately 1.7 ml of ink – more than twice as much as a standard converter. Refilling is done directly from the bottle; cartridges are not compatible.
- Hexagonal screw cap with inner cap: The six-sided cap closes with approximately one full turn, sits securely in the hand, and doesn't roll off the desk. The inner cap seals the nib airtight and prevents it from drying out.
- Completely dismantlable: Hex wrench and silicone grease are included. Piston seal, O-rings, and all individual parts can be maintained and replaced at home – without a repair service.
- Cap postable: Snaps securely onto the rear grip end (O-ring fixation) and extends the pen to approximately 167 mm – for writers who prefer greater length.
Application & Tips
- Choose nib size: EF produces fine, precise lines – ideal for small handwriting and detailed notes on smooth paper. F is the most popular everyday size. M is suitable for fluid journaling. B and 1.1 (broad nib) work with line variation and are suitable for handwriting, headings, and decorative text.
- Refill ink: Turn the piston knob counterclockwise, fully immerse the nib in the ink bottle, then screw the piston knob back in. For maximum fill: pump the piston several times up and down, then briefly hold the pen nib-up to expel any remaining air.
- Ink compatibility: All standard fountain pen inks based on water can be used. Shimmering and document-proof inks also work – with pigmented inks, more frequent flushing is recommended, as the piston mechanism can otherwise become stiff.
- Cleaning: Flush with lukewarm water every two weeks or when changing inks. If needed, lightly coat the piston mechanism with the included silicone grease to keep the seals smooth.
- Paper recommendation for EF: The EF nib shows its best writing performance on lightly coated, smooth paper. On very absorbent paper, the ink can flow more strongly, as the ink flow of ECO nibs is rather generous.
- First use: TWSBI tests every nib at the factory using a dip test – a slight ink residue in the nib is normal. Flush briefly with water before first refill.
For Fountain Pen Enthusiasts
The writing nibs of the TWSBI ECO are manufactured by Jowo in Germany and use Western sizing standards – the sizes are therefore broader than Japanese comparative values. The bronze-colored PVD coating sits on the stainless steel writing nib and is purely cosmetic; the steel underneath determines writing performance. For those who like to combine various ink colors, the ECO is an easy-care companion: thanks to complete disassembly capability, the nib, feed, and piston unit can be thoroughly separated, allowing even stubborn color residues to be completely removed. The Serpentine color design is created through a new injection molding coloring technique – the color distribution is random in each specimen and not reproducible, making each pen a unique piece.
Technical Specifications
| Model / Series: | TWSBI ECO Serpentine with Bronze |
| Color / Material: | Translucent acrylic resin, green-marbled (Serpentine); accents and clip in bronze PVD finish |
| Length (closed): | approximately 139 mm |
| Length (without cap): | approximately 132 mm |
| Length (cap posted): | approximately 167 mm |
| Barrel diameter: | 12.8 mm |
| Grip diameter: | 9.1 mm |
| Weight: | approximately 21 g |
| Filling system: | Integrated piston filler (no cartridge/converter operation) |
| Ink capacity: | approximately 1.7 ml |
| Writing nib: | Stainless steel, bronze-colored PVD coating, Jowo manufacturing (Germany), Western size specifications |
| Available nib sizes: | EF, F, M, B, 1.1 (broad nib) |
| Cap: | Hexagonal, screw closure, postable, with inner cap |
| Origin: | Taiwan (TWSBI) |
| Scope of delivery: | Pen, hex wrench for disassembly, silicone grease, cardboard packaging |