The TWSBI Eco Cosmos Blue with Onyx Fountain Pen blends affordability, durability, and elegant design in one sleek writing instrument. Featuring a Cosmos Blue cap and piston knob paired with onyx black metal accents, this pen delivers a modern aesthetic that stands out on any desk.

With its clear barrel, you can easily view the ink level and internal piston-filling system—offering both function and visual appeal. The polished stainless steel nib, engraved with the TWSBI logo, ensures a smooth, consistent writing experience, available in multiple nib sizes to suit your style.

Designed for convenience and longevity, the Eco can be fully disassembled for cleaning and maintenance, with tools and instructions included.

Equipped with a durable stainless steel nib, engraved with the TWSBI emblem, the Eco Cosmos Blue comes in a range of nib sizes to suit both beginners and experienced writers. Whether you're journaling, note-taking, or sketching, the pen delivers a consistently smooth and expressive writing experience.

Key Features:

• Model: TWSBI Eco Cosmos Blue with Onyx
• Filling Mechanism: Built-in piston-fill (no cartridges required)
• Barrel: Transparent resin for full ink visibility
• Cap & Piston Knob: Deep plum acrylic with faceted design
• Trim: Onyx dark grey metal accents
• Nib: Stainless steel, available in multiple sizes
• Cap Top: Embossed with the TWSBI logo
• Ideal For: Everyday writing, beginners, enthusiasts, and fountain pen collectors

Elevate your writing with the TWSBI Eco Cosmos Blue — where function meets form in a sleek, piston-filled masterpiece.

A standout feature of the TWSBI Eco is its ability to be fully disassembled for cleaning and maintenance. Each pen comes with the necessary tools and instructions for disassembly, though this feature is recommended for experienced users and is not required for everyday use. Please note that disassembly is done at your own risk.

Discover the TWSBI Eco Cosmos Blue with Onyx and enjoy a premium fountain pen experience at an affordable price, with the option to customize and maintain your pen as needed.

With a history of more than 40 years of manufacturing, including producing high-end pens for other brands, Ta Shin Precision decided to start selling under their own brand, TWSBI. The name TWSBI is made up from TWS and BI. ‘TWS’ is the reversed initials of the phrase ‘San Wen Tong’, translated Hall of Three Cultures, and ‘BI’ literally means writing instrument.

Limited Stock

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A quick no brainer guide in choosing nib sizes in an overly complicated fountain pen world:

• If you write small, go with an Extra Fine.
• For the normal writer, Fine is the most popular.
• If you tend to lean on a bigger font, Medium will be perfect.
• Broad is for statements!! Sign a check in Broad, write a header in Broad, do some coloring/shading in Broad.
• Stub nibs are italic in writing style (great for writing in special cards or invitations).