Opus 88 #12 Replacement Fountain Pen Nib — JoWo #6 Nib, Feed & Housing

A Drop-In Nib Unit, Ready to Write

The Opus 88 #12 is a complete replacement nib assembly, sized to the JoWo #6 standard — stainless steel nib, feed, and screw-in housing, sold as one unit rather than a bare nib. Swapping it into a compatible Opus 88 pen takes seconds: unscrew the existing nib section, thread this one in, and you're writing with a new line width or grind without sending the pen anywhere.

Fit & Compatibility

This nib unit fits Opus 88 pens built around the Jowo #6 housing, including the Demonstrator, Demonstrator Yellow, Jazz (Demonstrator and Solid Color), Omar (2020 and Demonstrator), Heart Sutra, and Sonata. Because it uses the standard JoWo #6 threading, it also fits many other JoWo-compatible fountain pens beyond the Opus 88 line.

Note: this housing does not fit the Opus 88 Bela, Flora, or Flow — those models use a different nib mount. Check your pen model before ordering.

What's Included

Each nib unit comes complete with the stainless steel nib, feed, and threaded housing — plus a small spare O-ring seal for the section threads, and its own compact gift box for safe storage of nibs you're not currently using.

Available Sizes at Shosai

We carry the Opus 88 #12 in:

• Fine (F) — the most versatile everyday width
• Medium (M) — broader and wetter, good for shading inks
• Broad (B) — a bold, generous line
• 1.5 mm Stub — an italic-style grind for crisp line variation
• Flex Extra Fine — a responsive nib that widens under pressure, fine at rest
• Flex Fine — the same flexible response with a slightly broader baseline

Extra Fine (EF) exists in the Opus 88 #12 line but is not currently in stock at Shosai — reach out if you'd like us to source it.

At Shosai

Every nib is inspected before it leaves our Gatineau boutique. Available in-store and online, serving the Ottawa–Gatineau National Capital Region with shipping across Canada. If you're unsure which width or grind is right for your pen or your handwriting, we're happy to help you choose.

Bilingual service — English and French.