Opus 88 Harmony Fountain Pen — 2025 Mocha Mousse Edition

A Softer Take on a Familiar Comfort

The Opus 88 Harmony 2025 Mocha Mousse pairs an unexpected color with a familiar name. Designed as a companion to Pantone's 2025 Color of the Year, the pen doesn't chase the obvious brown — instead, it offers a lightly tinted lavender demonstrator body, with warm ivory resin at the grip, finials, and end cap, and rose gold trim throughout. It's a quieter, more contemplative read on the coffee-toned inspiration behind it: soft rather than rich, restful rather than indulgent.

Design & Construction

The Harmony is built for comfortable daily writing rather than display-only handling — a lightweight, well-balanced pen with a semi-translucent barrel that lets you see the ink level and nib at a glance. Capped, the pen measures approximately 145.3 mm; the body alone is approximately 129.0 mm, with the cap adding approximately 65.5 mm when posted, for a posted length of approximately 170.2 mm. Body diameter is approximately 14.0 mm, cap diameter approximately 15.5 mm, and the pen weighs approximately 24 g. Rose gold-plated trim — clip, cap band, and nib — runs throughout, warming up the cool lavender tone of the resin.

The pen ships in an Opus 88 gift box with a glass eyedropper pipette included for filling.

Eyedropper Filling System & Shut-Off Valve

The Harmony uses a Japanese-style eyedropper system with a piston-operated shut-off valve, controlled by unscrewing the blind cap at the end of the barrel. An ebonite piston and rubber gasket seal the feed off from the barrel when fully closed, reducing the risk of leaks or ink burping — useful for a pen that travels, including by air. During long writing sessions, leave the valve open to take full advantage of the pen's ink capacity, approximately 2.5 ml.

To fill: unscrew the grip section from the barrel, use the included glass pipette to draw ink, deposit it into the barrel until about three-quarters full, and reassemble — avoid overfilling, as this can cause leaks. Before writing, unscrew the blind cap to release the shut-off mechanism; tighten it again before travel.

Nib Options

The Harmony Mocha Mousse is fitted with a rose gold-plated stainless steel JoWo #6 nib, available in:

• Extra Fine (EF) — a precise, controlled line for small handwriting
• 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 adding crisp line variation to every stroke

Opus 88 nibs tend to write slightly broader than equivalent Japanese sizes — if you usually reach for a Pilot or Sailor fine, consider sizing down one step.

Manufacturer Warranty

Opus 88 fountain pens are backed by the manufacturer's warranty against defects. If your pen ever needs attention, bring it to our Gatineau boutique and we will coordinate directly with Opus 88 on your behalf. Full details, eligibility, and delivery options →

At Shosai

The Opus 88 Harmony 2025 Mocha Mousse is a special edition, produced in limited numbers to mark Pantone's Color of the Year — once our allocation sells out, it's unlikely to be restocked. Available at Shosai's Gatineau boutique and through our online store, serving the Ottawa–Gatineau National Capital Region and fountain pen enthusiasts across Canada. Each pen is inspected before shipping. If you have questions about nib selection, ink pairing, or filling an eyedropper pen for the first time, we are here to help.

Bilingual service — English and French.