TWSBI

TWSBI Obsidian Fountain Pen

Variant
Regular price $122.50
The TWSBI Obsidian fountain pen features a dark gray–black swirled acrylic resin body paired with rose gold–plated trim and a matching rose gold–plated stainless steel nib, similar in size to the TWSBI 580 nib. Like all TWSBI pens, it uses the brand’s signature piston filling system and is fully user-serviceable. A built-in ink window lets you easily keep an eye on your ink level.

While the cap can technically be posted, TWSBI recommends against posting it, as doing so may scratch the barrel.

The Obsidian is a limited-edition release and will not be produced on an ongoing basis.

TWSBI designs its pens to be taken apart and reassembled, allowing users to fully experience the traditional mechanics of a fountain pen. Each pen includes a wrench and silicone grease for long-term maintenance - these accessories are not meant for immediate use. If you choose to disassemble the nib and feed, please use extra care, as the feed is delicate.
  • Choose from Fine or Medium nib sizes
  • Nib material: Stainless steel
  • Length Overall (Closed): 5.58in (141.8mm)
  • Filling Mechanism: Piston
  • Body Material: Resin

TWSBI (pronounced TWIZ-BEE) has become a staple in the fountain pen community, known for its high-quality, piston and vacuum-filling demonstrator pens at an exceptional value. Though it may seem like a newer brand, TWSBI’s history spans over 50 years as Ta Shin Precision, an OEM manufacturer producing parts for well-known brands. A decade ago, the company shifted to designing its own pens, combining traditional craftsmanship with modern innovation.

With a name inspired by Chinese calligraphy, TWSBI is dedicated to creating durable, high-performing pens featuring smooth stainless steel nibs, excellent cap seals, and transparent designs that showcase their intricate filling mechanisms. Their user-serviceable approach, with included tools for maintenance, makes them a favorite among writers, professionals, and pen enthusiasts looking for reliability, style, and a hands-on writing experience.