TWSBI Eco Fountain Pen - Slate Blue with Onyx

A quieter kind of confidence

This the limited edition Eco Slate Blue, that sits in between blue and blue grey, depending on the light. Trimmed with black Onyx plating to give it visual strength. It uses the reliable Eco piston filling mechanism for high ink capacity and smooth writing nib.

What sets it apart

• A colour way that conveys reliability and strength
• Easy to use piston mechanism, for high ink capacity
• Straightforward ink match with "work" blacks and blues
• Crystal clear polycarbonate body shows ink movement and level
• A calming feeling despite the black trim

Feel in the hand

This release is a smart looking pen that turns a conservative blue colour way into something special by offsetting the blue with black. Feels calm, yet strong. You will pick it up when you know you have a lot to write.

Who it’s for

• You want a first serious fountain pen that won’t limit you
• You’re building a daily writing or sketching habit
• You appreciate understated design over flashy colours
• You want to actually see and understand your ink
• Professionals who want personality, but not attention

Not for

• You prefer compact, pocket pens.
• You have petite hands and find full size pens too wide
• You want the convenience of cartridge/converter systems
• You don’t want to think about maintenance at all

Practical tips

• Only grease the piston if it starts feeling stiff. Tools and instructions are included in the pen box

FAQs

Is this good for beginners?
Yes, it's widely considered one of the best entry points because of its reliability and value

What’s different about the onyx nib?
Primarily aesthetic, but it changes the emotional feel with the more muted, and refined appearance

Does it come with ink?
No, this is designed for bottled ink use. You can use any bottled ink that is labelled for fountain pens

Can I take it apart?
Yes, TWSBI includes tools for maintenance, though it’s not needed often

What’s included

• TWSBI Eco Fountain Pen Slate Blue with Onyx
• Wrench
• Silicone grease
• Simple gift box
• Free nib tuning from LarryPOST

Ink pairing suggestions

• Blue-black inks to deepen the slate tone
• Warm browns to contrast against the cool body
• Shading inks to enjoy the variation when used in wider nibs

Build your practice

• Collect the TWSBI Eco plated series
• Pilot Pen wrap to hold multiple pens
  
• A notebook that shows shading (eg. Midori)

Specifications

• Brand: TWSBI
• Brand series: Eco
• Launch: March 2025
• Origin: Taiwan
• Nib: Black Stainless steel
• Nib sizes: EF, F, M, B, 1.1mm stub
• Filling system: Piston filler (1.8mL)
• Body: Transparent polycarbonate
• Cap: Twist
• Diametre: approx. 13mm
• Length: approx. 139mm (capped)
• Weight: approx. 21g (capped)
• Comparable size: Lamy Safari, Pilot Metropolitan

This is one of those pens you could happily reach for every day.