OPUS 88 Mini Pocket Fountain Pen - Traditional Eyedropper Filling, Clear Acrylic Demonstrator, Stainless Steel Nib

OPUS 88 Mini Pocket Fountain Pen - Eyedropper Demonstrator

A true eyedropper pen that fits in a shirt pocket. Instead of a cartridge or a small converter, the entire clear acrylic barrel is the ink reservoir, so you fill it once and write for weeks. At just 119 mm capped, it slips into a pocket, a planner loop, or the smallest pen case, and the transparent body lets you watch your ink level and your ink colour all day long.

Why you will love it

• Traditional eyedropper filling - fill the whole barrel with a pipette for an enormous ink capacity, far beyond a standard converter.
• Clear acrylic demonstrator - the crystal-clear barrel shows off every shading and sheening ink you own.
• Genuinely pocketable - 119 mm closed makes it a compact carry that still posts to a comfortable writing length.
• Stainless steel nib - smooth, forgiving, and reliable for daily notes, journalling, and sketching.
• Shut-off valve design - OPUS 88's signature valve system lets you close the ink flow when the pen is stored or travelling.

Specifications

• Brand: OPUS 88
• Type: Mini pocket fountain pen, demonstrator
• Filling system: Traditional eyedropper filling (pipette included style filling, barrel holds the ink)
• Body material: Clear acrylic
• Nib material: Stainless steel
• Capped length: 119 mm
• Ink: Bottled fountain pen ink only

How to fill it

1. Unscrew the barrel from the section.
2. Use the eyedropper or pipette to fill the barrel with bottled fountain pen ink, leaving a little air space.
3. Screw the section back on firmly, then open the shut-off valve at the end of the pen to start ink flow.
4. Close the valve when you finish writing or before packing the pen for travel.

Care

Use bottled fountain pen ink only, avoid iron gall and shimmer inks in an eyedropper, rinse the barrel with cool water between ink changes, and keep the valve closed during transport to prevent burping.

Frequently asked questions

What is eyedropper filling?

Instead of a cartridge or converter, you fill the pen's entire barrel with ink using a pipette. That gives a very large ink capacity, so refills are rare.

How long is the pen?

It measures 119 mm when capped, which is why it works so well as a pocket or planner pen. Posting the cap brings it to a comfortable writing length.

Can I use ink cartridges instead?

No. This is a dedicated eyedropper pen, so it is designed for bottled fountain pen ink filled directly into the barrel.

What does the shut-off valve do?

Turning the knob at the end of the pen closes the ink channel. That keeps ink from flooding the nib while the pen is stored or carried, and you simply open it again before writing.

What nib sizes are available?

This pen uses a stainless steel nib. Please select the nib size shown in the options above before adding it to your cart.

Which inks should I avoid?

Stick to standard bottled fountain pen inks. Shimmer, pigment, and iron gall inks are not recommended in an eyedropper pen because they can clog or stain the acrylic.

Is it a good first fountain pen?

Yes, if you enjoy using bottled ink. The steel nib is smooth and easy going, and the huge capacity means you can write for a long time between fills.