The Opus 88 Demonstrator fountain pen is a truly unique writing instrument. This large non-postable pen is an eyedropper-filled pen with a piston operated shut-off valve. Featuring a sharp alternating material scheme of frosted and clear resin, this pen’s design stands on its own. It has a sleek black clip and a silver stainless steel #6 JoWo nib and includes a glass eyedropper to fill the pen with your favorite ink.
Note: JoWo is transitioning their nib designs from the old scroll pattern to a more simple design. Stock is currently mixed; what you receive may not necessarily match what is photographed.
An ebonite piston and rubber gasket seals the feed off from the barrel when fully depressed, reducing the risk of leakage and burping. By unscrewing the blind cap and loosening the rod at the rear of the barrel, you open up the ink flow to the feed. During long writing sessions, leave the shut-off valve open to take advantage of the impressive ink capacity. Having a completely clear pen body allows you to see both your current ink level and your nib while capped.
- Opus 88
- Fountain Pens
Whether or not the barrel of the pen is translucent, allowing you to see the ink and filling mechanism inside.
- Body Material
- Cap Rotations
For pens with a screw-cap closure, how many rotations it takes to uncap/recap the pen.
- Cap Type
How the cap is opened/closed from the barrel of the pen. Some common options include Snap-Cap, Screw-Cap, Magnetic Cap, or Capless (no cap).
- Compatible inks & refills
Which ink this pen will accept. Choices include bottled ink and various styles of pre-filled ink cartridges.
- Bottled inks
- Filling Mechanism
How the pen fills with ink. Click here to watch our video tutorial on common filling mechanisms.
- Grip Material
- Nib Size
- Extra-Fine, Fine, Medium, Broad, 1.5mm Stub
- Nib Color
- Nib Material
Whether or not the cap fits securely onto the back of the barrel when open.
Whether or not the nib/tip can retract into the body of the pen (usually for click or twist-open style pens).
- Diameter - Body
- 14.9mm (0.59in)
- Diameter - Cap (without clip)
- 16.5mm (0.65in)
- Diameter - Cap (with clip)
- 21mm (0.83in)
- Diameter - Grip (mm)
Measured from the place most people choose to rest their fingers, which varies with each pen.
- Length - Body
The measurement from the back end of the barrel to the tip of the nib.
- 136.5mm (5.37in)
- Length - Cap
- 63.6mm (2.50in)
- Length - Nib
The measured length of the visible portion of the nib when it is installed in the pen, from grip to tip.
- 23mm (0.91in)
- Length - Overall (Closed)
- 147.6mm (5.81in)
- Weight - Body
If a converter is included with the pen, this weight is reflected in the total.
- 17g (0.60oz)
- Weight - Cap
- 10g (0.35oz)
- Weight - Overall (g)
- Max Ink Capacity - Eyedropper
The maximum volume of ink that can fit in the pen when filling the entire barrel of the pen via eyedropper.
How do I fill a fountain pen with ink?
It depends on the pen's filling mechanism, which you can find in the Technical Specs section above.
Here's a quick definition of the most common filling mechanisms:
Cartridge - A small, disposable, sealed plastic reservoir that holds fountain pen ink. These come pre-filled with ink, and typically you just push to insert them into place and you'll be ready to write!
Converter - A detachable and refillable ink reservoir that allows you to use bottled ink in a cartridge-accepting pen. Typically you will install the converter into the grip section, dip the nib/feed into the ink, and twist or pull the converter knob to draw ink into the converter. Here's a video for how to fill a cartridge/converter pen using a LAMY pen as an example.
Eyedropper - A pen that utilizes the entire barrel as a reservoir for ink. Ink is directly filled into the barrel, allowing for a high ink capacity. Here's a video on how to do it!
Piston - A type of filling system that uses a retracting plunger inside a sealed tube to draw ink into a pen. They are typically either twist or push-operated. These pens cannot accept cartridges or a converter, and only fill from bottled ink.
Vacuum - A push-style piston that uses pressure to fill the large pen body with ink. They seal the ink chamber when closed, making it ideal for flying without risk of leaking.
You can learn more with our Fountain Pen 101 video on Filling Mechanisms on YouTube.
How do I clean a fountain pen?
It depends on the filling mechanism, but it mostly comes down to flushing it out with water, and sometimes a little bit of Pen Flush if the ink is really stuck.
It's a bit easier to show than to tell, so we've put together a few quick videos showing you the process:
How to Clean a Cartridge/Converter Pen
How to Clean an Eyedropper Pen
How often do I need to clean my fountain pen?
We recommend a good cleaning every 2 weeks, and any time you change ink colors.
Water will usually do the trick, but we recommend you use our Goulet Pen Flush if the ink has been left in the pen for a while and could have dried up, or when you’re switching ink colors.
My pen won’t write! What do I do?
First things first... make sure you have ink in the pen! Be sure that the ink cartridge or converter is seated properly in the pen, and that you aren't out of ink.
We always recommend you give your pen a good cleaning first, using our Goulet Pen Flush, or a drop of dish soap in some water. New pens often have some machining oil residue left in the feed, so a good cleaning often does the trick first.
If that still doesn't work, try priming the feed. This consists of either dipping your pen nib and feed in ink, or forcing ink from the converter down into the feed.
If it’s still not working after that, please reach out to us so we can help!
What’s your return policy?
You can submit a return request within 60 days of your order date. You can read all our Return Policies here.
To initiate a return, please submit a request at the Return Portal. Our Customer Care team might reach out to you for more information.