TWSBI Vac 700R Iris Review: A Rainbow Fountain Pen With Real Character

Introduction

Some fountain pens impress with price tags or pedigree. The TWSBI Vac 700R Iris impresses with personality. It is an iridescent, rainbow-hued vacuum-filler that looks unlike almost anything else in its price bracket, and it happens to be a genuinely excellent writer.

TWSBI has long been a favorite among fountain pen enthusiasts because of its value proposition: well-built pens, easy cleaning, user-serviceable mechanisms, and mostly demonstrator designs that let you see exactly how much ink remains. The Vac 700R Iris takes that practical foundation and wraps it in one of the most flamboyant finishes the brand offers.

Who This Pen Is For

The Iris finish is a lot of fun. It is iridescent and rainbow-colored, and each pen looks slightly different because the technique produces different color effects on every nib and barrel. It is absolutely beautiful, but it may not be the best pen to pull out in a business meeting. If that matters to you, TWSBI also makes the Vac 700R in a transparent demonstrator version, which suits a more conservative setting.

At home, though, the Iris is one of the best pens you can pick up for journaling. When you look down at a collection full of black-and-gold business pens, seeing a rainbow pen in this kind of color is genuinely refreshing.

Design and Build

The body is resin, which means plastic, and the cap screws on rather than popping off quickly the way it does on something like a Lamy Safari. The pen measures about 15 millimeters in diameter, which is on the thicker side, but the section flares right behind the feed where the vacuum mechanism terminates, so it remains very comfortable to cradle and write with for long sessions.

The Vac 700R is available in extra fine, fine, medium, broad, or stub nibs, and the clear demonstrator version is a good pick if you want to watch your ink level in a more understated package.

The Vacuum Fill Mechanism

The Vac 700R uses a vacuum fill system, similar in concept to the Pilot Custom 823, though the mechanism works a bit differently. The Pilot’s fill feels effortless, with ink rushing into the reservoir in one smooth plunge. The TWSBI takes a little more work: a single plunge may only produce a partial fill, so you often need to expel air, push the plunger carefully, and plunge again to get a solid fill.

The payoff is substantial capacity. The pen holds about 2.5 milliliters of ink, which is a lot, and a recent fill in testing nearly filled the entire barrel.

There are two practical habits to learn. First, you need to vent the pen while using it by unscrewing the back slightly so air can flow through. Second, once you secure the plunger it cuts off the feed, which makes this a very safe pen to fly with. Even with the vent loosened, the pen can still be posted, though that makes it a bit long.

The Cursive Smooth Italic Nib

The pen featured here started as a standard medium nib that was custom-ground into a cursive smooth italic by a nibsmith, which raised the roughly 80 dollar price of the pen to about 120 dollars with the custom work. It was worth every penny and turned it into one of the most interesting writers in the collection.

The cursive smooth italic delivers really nice line variation, and it seems to shine most as you write faster. It thrives on the accelerated rhythm of cursive writing, and the more you give yourself over to that flow, the more reward you get back from the nib. That makes it a great answer for anyone a little bored of fine and medium nibs and looking for more character and variety on the page.

How It Writes and What It Costs

As a writer, this is a fantastic, smooth, and precise pen. At around 120 dollars with custom nib work, it is one of the best values in pens: the nib, the shape, and the comfort feel comparable to a Pilot Custom 823 in every respect except the fill mechanism. Even at its stock price of roughly 80 dollars, it holds up remarkably well.

There is also something liberating about the price. It is not a 500 or 1,000 dollar pen, so you do not feel the need to treat it as delicately as something more expensive. Like a car you have owned long enough to stop worrying about where you park it, it simply becomes more fun to own. It clips easily inside a jacket and makes a great companion for journaling wherever you happen to be.

Buying Advice

If you journal at home and want a pen with visual personality, the Iris version is the one to hunt down. If you need something more appropriate for meetings or the office, choose the transparent demonstrator instead.

If you are tempted by custom nibs, the cursive smooth italic grind transforms this from a good pen into a standout one. The extra cost is meaningful, but the result is a writer that easily earns its place as a benchmark against which other pens get compared.

Conclusion

The TWSBI Vac 700R Iris is a rare combination of flair and function: a large-capacity vacuum-filler, a comfortable thick-bodied writer, and one of the most colorful pens available at its price. It rewards cursive writers, welcomes everyday use, and delivers value that few pens at this level can match. If variety and character are what you are chasing, this pen deserves a spot in your rotation.