TWSBI Fountain Pen ECO Carrara with Onyx B

The TWSBI ECO Carrara with Onyx is a piston filler with an aesthetic that comes from the injection molding process – and which therefore turns out different each time: Cap and piston knob display a whitish-gray marble pattern that recalls Italian Carrara stone. The corpus is completely transparent, fittings and nib are black-anodized. It is filled directly from the ink bottle – no converter, no cartridge, simply unscrew the end cap, dip, and pull back.

Special Features

• Marble look through injection molding: Carrara pattern on cap and piston knob is created by a special color technique in injection molding – no printing, no sticker. Each pen bears a slightly different pattern.
• Integrated piston mechanism: Ink is drawn directly from the bottle by turning the piston knob. Capacity: approx. 1.76 ml – considerably more than a conventional converter holds.
• Transparent corpus: The ink level is visible at any time without opening the pen. Practical for color changes and during long writing sessions.
• Black stainless steel nib with Onyx fittings: Nib and decorative parts are finished in Onyx and form a contrasting, monochrome counterpoint to the light marble cap. Nibs in western sizes made in Germany.
• Hexagonal cap: The faceted cap sits securely in the hand and does not roll off the desk. Can be safely posted on the rear end.
• Inner seal of the cap: A rubber ring on the cap thread provides an airtight seal – the nib does not dry out even during longer breaks.
• Completely disassemblable: The package includes a wrench and silicone oil to independently clean, lubricate, and maintain the piston mechanism and nib.

Application & Tips

• Filling: Unscrew the end cap, fully dip the nib into the ink, slowly pull back the piston knob. For maximum filling, repeat the process two to three times, then hold the nib upward and remove air bubbles by briefly pulling back again.
• Nib width EF: Very fine line, ideal for small script, tight line spacing in planners and bullet journals, and for more ink-intensive inks that look particularly brilliant on smooth, calendered paper. On slightly rough paper, EF nibs can catch slightly – smooth paper is recommended.
• Nib width F: The most popular width for daily use – uniform ink flow, clear script.
• Nib width M: Soft, saturated line for larger script, journaling or correspondence.
• Nib width B: Expressive line for headings, signatures, or layouts with contrast levels.
• Nib width 1.1 (Broad nib): Italic-like line with line width variation – suitable for decorative fonts, lettering, and calligraphic everyday script.
• Ink: Only use liquid fountain pen ink from the bottle. India ink products and pigmented inks with high solid content can clog the piston and feed.
• Cleaning: Rinse thoroughly with clear, lukewarm water when changing colors or after longer breaks until the runoff is clear. For stubborn ink residue, the pen can be completely disassembled using the included tool.
• Paper: Smooth, ink-resistant paper shows the full effect – with absorbent paper, it is better to choose drier ink, especially with the EF nib.

For Piston Filler Enthusiasts

The nibs of the TWSBI ECO are manufactured in Germany and follow western width standards – EF is correspondingly finer than Japanese EF nibs. The Carrara marble pattern is created by a special color injection process in injection molding: white and gray plastic layers are mixed together in liquid form, creating organic veining and making each pen unique. Those who want to keep the piston mechanism smooth long-term can regularly apply the included silicone oil to the piston seal ring – maintenance that is often overlooked with piston fillers but considerably extends the pen's lifespan.

Technical Data