on saleOpus 88 Demonstrator Fountain Pen - Clear

Product Code OP-96083900EF

In Stock

out of stock

on saleOpus 88 Demonstrator Fountain Pen - Clear

Product Code OP-96083900EF

In Stock

out of stock

Nib Guide

Not sure which size nib is best for you?

Try our Nib Nook tool to view and compare nib widths using our writing samples. Learn more ›

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.


Customer Reviews

Based on 89 reviews
Eric P.
One annoying flaw in a beautiful pen

Stunningly designed, expertly crafted, and the best filling system yet invented, the eyedropper with shut-off valve. I love everything about it. Except for one thing that annoys me every single time I use it. It takes four (4) full turns to screw the cap off. Two full turns would be excessive, but four is ridiculous. I guess I would add that the cap threads are not very smooth, and I ended up putting some silicone grease on them. For comparison, my Twsbi Diamond 580 takes just one turn, and the screw threads are silky smooth and dependable. I'm certainly not the only person who has complained about this problem. I would probably buy other Opus 88 pens if not for this fatal flaw. And it's impossible to recommend them to others. It would be a simple fabrication fix . . . if anyone at Opus 88 is listening . . .While you're at it, produce one of these in a frosted finish, it would be stunning.

Great for Journaling

I had heard great things about this pen and wanted to try it out. It looks beautiful in person and is a perfect way to showcase your ink. It is easy to fill, comfortable to hold and the stub nib is wonderful. It has quickly become one of my most reached for fountain pens while journaling.

Underwhelming at first, but Quickly Became a Favorite

So when I first got this pen out of the box, it seems like light acrylic and the **** on the back squeaked and my first thought was "I payed $120 for this??" But I duly put a little silicon grease on the back threads, which totally stopped the squeaking, and filled it up with Diamine Aurora Borealis - one of my favorite inks - and it knocked my socks off! The weight is much better full, the grip section is the perfect thickness for my (mens L-XL) hands during long writing sessions, and the broad Jowo nib is very wet and smooth. Plus, it holds a lot of easily visible ink. I anticipate that this one will be continually inked for the foreseeable future (shut off valve means less risk of drying out!), and it's quickly become the first pen I reach for. Now I see what all the fuss is about. I definitely recommend it.


Wrote like a gem. Weight and thickness was right on for me. FYI I swapped the F nib out for a Conklin medium and it fit just fine


Wrote like a gem. Weight and thickness was right on for me. FYI I swapped the F nib out for a Conklin medium and it fit just fine

FAQs about Fountain Pens

How do I fill a fountain pen with ink? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

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! Check out our quick guide here.
  • 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. Check out our video on how to use a vac filler here.

Check out more info on these filling mechanisms including a video on how to fill each one on our blog.

How do I clean a fountain pen? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

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 often do I need to clean my fountain pen? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

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? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

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? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

You can submit a return request within 30 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.

Please note we are unable to accept a return of any Namiki or Sailor Bespoke fountain pen for any reason once it has been used with ink. Please thoroughly inspect and dry test the pen before use.