TWSBI Eco Fountain Pen - Plum with Onyx Trim and Nib
A plum Eco that shifts depending on ink choice
The TWSBI Eco Plum is a piston filling fountain pen with a deep crimson body and subtle black trim. The transparent barrel means the overall appearance shifts depending on the ink inside, moving between warmer red and cooler pink tones depending on what you fill it with. It remains a practical Eco at its core, with the same high ink capacity and reliable piston mechanism.
What sets it apart
- High capacity piston filling system for long writing sessions
- Smooth, consistent steel nib, across a range of sizes
- Deep plum tone with subtle warmth and depth
- Transparent barrel shows ink level and influences overall look
- Appearance changes depending on ink choice
Feel in the hand
In hand, the Plum feels like a standard Eco with a warmer visual tone. The writing experience is unchanged, but the body colour gives it more presence on the desk, especially when paired with red or pink inks.
Who it’s for
- Writers who like demonstrators with warmer colour tones
- People who enjoy matching ink colour to pen appearance
- Users wanting high ink capacity with a bit more visual character
- Everyday writers who prefer subtle variation over neutral finishes
- Collectors of the Eco colour series
Not for
- Users who prefer neutral, monochrome or fully opaque pens
- Those wanting cartridge or converter simplicity
- Writers looking for a metal or luxury body feel
- Users expecting nib variation or flex performance
Practical tips
The visual tone of the pen changes noticeably depending on ink colour. Lighter pink inks shift the appearance toward a softer look, while darker reds make it feel more saturated and formal. The effect is subtle but noticeable in good lighting.
FAQs
Is it a limited edition?
Yes, it is typically produced in a single run and then discontinued.
Is the Plum fully transparent?
Yes, it is a demonstrator with a completely clear barrel, allowing ink visibility. Only the cap and turning knob are opaque.
Does it use cartridges or converters?
No, it uses a built-in piston filling system.
Is it suitable for beginners?
Yes, it is one of the most beginner-friendly piston fillers available
Can it handle document and shimmer inks?
Yes, with regular cleaning recommended
What nib does it use?
TWSBI stainless steel nib with a black onyx coating.Â
What’s included
- TWSBI ECO Plum Fountain Pen
- Wrench
- Silicone grease
- Simple pen box
- Instruction booklet
- Free nib tuning by LarryPOST
Ink pairing suggestions
- Red inks enhance the warm tones of the body
- Pink inks shift the overall look to a softer appearance
- Deep blue inks create strong contrast inside the barrel
- Standard black inks give a more formal overall presentation
Build your practice
- Eco plated range work well together as a collection due to interchangeable nibs
- Replacement nibs allow for easy changes in writing feel
- Pilot Iroshizuku or De Atramentis Document inks both behave consistently in piston fillers
Specifications
- Brand:Â TWSBI
- Brand series:Â Eco
- Launch:Â October 2025
- Origin:Â Taiwan
- Nib: Black Stainless steel
- Nib sizes:Â EF, F, M, B, 1.1mm stub
- Filling system:Â Piston filler (1.8mL)
- Body:Â Transparent polycarbonate
- Cap:Â Twist
- Diametre:Â approx. 13mm
- Length:Â approx. 139mm (capped)
- Weight: approx. 21g (capped)
- Comparable size:Â Lamy Safari, Pilot Metropolitan
Reliable Eco writing experience, with more warmth in the body.
