Sea of Troubles

Review: TWSBI Pens

TWSBI is a manufacturer of fountain pens. Long a contract manufacturer for other brands, they are now developing and producing their own products. I recently bought two pens — the Diamond Mini and the Vac700 — and wanted to share my first impressions.


The mini is a piston filler, with a surprisingly large ink reservoir given its diminuitive size. It comes in three colour schemes: a clear demonstrator, an all-black variant and a combination (black except for a clear barrel) called “classic”. I bought the classic with a 1.1mm stub nib. I haven’t really used a stub nib before, but the line variation lends an interesting character that I’m enjoying. It’s inked with Noodler’s Forest Green, which I’ve not previously warmed to, but is wonderful with this nib. The stub nib is very usable, far more than I expected. It’s possible to write very quickly, so long as you keep the nib at the right angle: flat onto the paper.

By itself, the Mini is far too small in my (non-trivial) hands. Posted, though, it’s the length of a normal pen and about right. Wonderfully, the cap screws into the back of the pen for stability. There’s a bit of a trick to posting it such that the clip isn’t poking the webbing of your hand, but it becomes habit quite quickly.

TWSBI sells a Diamond 50 ink bottle for use with the Mini and its larger brothers the 530 and 540. It allows you to refill either by unscrewing the section and attaching the barrel directly to the bottle to draw up ink. This give a very full fill without any ink getting on the nib or grip; this saves on the otherwise inevitable ink stains on my fingers. Brian Goulet has a good video demonstrating this on the Ink Nouveau blog.

TWSBI Vac700

The Vac700 is a bit of a novelty; vacuum fillers aren’t that common in modern pens. The key downside of the Vac700’s fill mechanism is that it’s hard to get a complete fill from an ordinary bottle. While the vacuum is drawing the ink up, it has to fight gravity to do so. Typically, this means you can’t practically get the pen more than about two-thirds full.

To this end, TWSBI invented the Vac 20 bottle for use with the Vac700. It’s an airtight ink bottle that the pen screws into, and allows you to invert the ink above the pen. Now gravity and the vacuum work together to get a great fill. Two pumps and the pen is usually full to capacity. Again, the Ink Noveau video explanation is the best I’ve found.

I had heard rumours about the nibs running dry, so I shied away from the EF and got an F. Either I was lucky or I shouldn’t have worried; it writes wonderfully. Not that wet, but certainly not concerningly dry. On a number of papers, it has more bleed through (with Noodler’s Navy or Purple Martin) than Forest Green in the Mini’s much wider nib!

The Vac700 is a full-size pen; it feels a bit bigger than a Montblanc 146 or a Lamy Safari in my hand. While it’s possible to post it, it feels much less stable to me in that configuration — it’s far too long and back heavy. I typically end up holding the cap in my left hand while I write. The clear demonstrator, while a bit of a novelty, is still good fun.

Final thoughts

For a brand I hadn’t really heard of a month ago, TWSBI has blown me away. It’s a powerful combination of modern design, effective performance, and astonishingly low price: the Mini is $50 and the Vac700 $80. I’ve used fountain pens several times the price without quantifiably better performance, and quite a few worse. The release of the next mid-sized model — the 580, probably sometime in March — promises to be something special again.