Answering your TWSBI Eco Questions

The TWSBI Eco was announced….oh a while ago, and it’s been long awaited. Previously, the TWSBI 580 was the value TWSBI pen (and still is really, at $50). But with the $28.99 TWSBI Eco coming out, and with the same ink capacity as the 580, it almost seems too good to be true. 
I just got the new TWSBI Eco in my hands yesterday and I have seen a ton of questions coming in about the pen. It’ll take a bit for me to be able to get you a video to answer your questions, so in the meantime I wanted to assemble this Q&A style blog post to answer your most pressing questions:
What nib does the Eco use? Can it take a nib from another TWSBI?
  • It appears to use the same nib as Classic and Mini, and they’re interchangeable but you have to physically pull the metal nib from the housings of the Classic or Mini to fit it into the Eco.
  • There is no nib unit to swap, must pull the nib (REALLY hard on the Classic)
  • Not many options for spare nibs in this size from other brands (none at Goulet), buying multiple Eco pens may end up being the most practical (if you can).
  • That all being said, the fins on the TWSBI feeds are extremely fragile. Removing the feed is not recommended.

Is the grip triangular like a Lamy Safari?

  • No, it’s not. Looking at the front of the grip, you can see three protrusions that stick up to help keep your fingers from sliding off the end, but they’re very small and don’t carry up the length of the grip. The majority of the grip is cylindrical.

What parts are swappable with other TWSBI pens?

  • The piston can swap with the 580, but then you can’t post either pen. But the guts of the piston mechanism appear identical.
  • The nibs swap with the Mini and Classic, but you have to pull just the metal nib out, the grips don’t swap.
  • The feed appears identical to the Classic
  • The cap of the 580 can kind of fit onto the Eco, but it’s not a perfect fit. I wouldn’t recommend it, and they don’t swap the other way around. 
  • The o-ring at the grip threads appears the same on the Eco as the 580.

How does it compare to the 580 and Mini?

  • Piston mechanism appears identical to 580.
  • It’s about the same overall size as the 580, longer than the Mini.
  • Ink capacity is similar to 580, larger than Mini, pushing close to 2ml.

Where does the name come from?

  • Eco = Economical…more affordable pen.
  • It doesn’t mean eco as in “eco-friendly”. Y’know, any more than a normal fountain pen is eco-friendly (cuz they all kinda are).

How do you disassemble the pen?

  • Exact same as 580, with different wrench (that I like better!)
  • Check out the 580 disassembly video I have, it’ll be the same method. 

The wrench is different, can they be used interchangeably with the original metal one? 

  • Yes, they work interchangeably. The red wrench isn’t super-tight on the Vac-700, but it works well on the Eco, 580, Mini, and Classic. The metal wrench works on the Eco. 

Can you use a TWSBI bottle to fill it?

  • Yes and no, grip does not remove, so it fills just like a normal pen would.
  • You can fill like any other pen from the cone insert directly in the bottle, but not from the cap of the bottle like the 580, Mini, and Classic.

How is it filled?

  • It’s a piston pen that operates just like all of the other TWSBI pens.

How much ink does it hold?

  • Appears similar to 580, just under 2ml at its max.

What are the dimensions?

  • From

How is the fit and finish?

  • Really nice, clean, better than I expected for this price point!

How does it post? Does the cap sit on the filler knob like the 580?

  • It does not post on the filler knob, no worries about blurting ink due to twisting the knob inadvertently. It has an o-ring on the barrel of the pen, just before the filler knob, that the cap sits on to hold it in place. Posted it’s a tad long, but light so it’s pretty usable even if you don’t have giant gorilla hands like me. 

What about the cap sealing?

  • It has an insert to help keep the nib wet. 
  • An o-ring around the grip threads helps seal up the cap.

When will you get more? 

  • Almost certainly we’re going to sell out of these pretty quickly, even as I’ve been drafting this post they’re flying out the door. It’s going to be into the first or second week in August before we expect a second shipment. I don’t have a firm date on the next batch, but you can sign up for an email notification on our site for a specific nib size you want so you know right when we have more. 
If I left anything out, just ask in the comments below and I’ll answer! I expect stock to be somewhat intermittent on Thanks so much 🙂 
Write On,
Brian Goulet
2017-10-11T14:06:48+00:00 July 22nd, 2015|Pen Reviews|10 Comments
  • Bourgeoisie

    This was very helpful. Thanks for posting!

  • ★ keri ★

    Thank you, Brian!

    It's so cool about it having a number 5 sized nib (from what it sounds like) – it's probably my favorite nib size (the next size down is sometimes a little too small, the 6 is often a hair too big to be comfortable). I bought it even before I even saw this, just because I was so delighted by a TWSBI that I didn't have to "plan" for – less than $30 is a good impulse price point – and now I'm even more excited! 🙂

  • Helder Cervantes

    I really love the design on this one. I'd buy one if it wasn't for the expensive shipping to Portugal. Waiting to see this pen's video review and writing test.

  • I already ordered mine earlier today. I saw them popping up from place to place and then saw the first review on Youtube this morning so I tapped my foot and waited patiently (I swear I was patient) and then there they were ready to order on Goulet. I'm so happy I can't wait to ink them up when they get here (did I say them? I ordered a black in medium and a white in fine). Of course if I'm buying new fountain pens I always have to treat myself to some new ink as well. I took the plunge and bought my first 4.5 oz bottle of Baystate Blue (and I didn't even notice until after I ordered it that the free pen is the Charlie pen, sweet! I love the Charlie pen I already have).

    A great day! Thanks Team Goulet!

  • tadaahhh

    when you have time to do a writing sample, could you please compare the stub to the stub on the 580? i am hoping it is as juicy. =)

  • paul in kirkland

    I'm on the mailing list to be notified when the fine nib is available for the mini. It's been many months now – should I just try to swap it out for my regular TWSBI nib?

  • Tom Johnson

    With all the blog entries coming in, I seemed to have missed this one. I think when I saw the cats I thought it was the Monday Matchup that I'd already seen. I just love this and love this ink, and it is wonderful to finally get these reviews back, dry time, drip test, etc. And three different papers! Thanks so much for this review.

  • Freddy

    As soon as the notification came in, I ordered two, one in each color and one with an extra fine nib and the other with a stub. The gift certificate I was holding for just this pen wouldn't seem to take in my order so I called. As always, it was just a great experience and everything got worked out beautifully. Naturally, it was time to add a new ink to try, as well as restocking my all-time favorite pure red, Sheaffer Skrip. So much for the Eco standing for Economical. LOL Now comes the pain of waiting for the mailman. 😉

    To say working with virtually any member of the Goulet staff, whether through e-mail, your site, or via telephone, is a pleasure is a huge understatement. Thanks to all of you for a job well done.

  • anaximander70

    I had a bunch of questions about this pen and I think you covered all of them. Thanks for a great post!

  • Paper_Queen

    Any suggestions for those of us filling from ink sample vials? Looks like my handy dandy syringe isn't going to be an option, drats (your earlier video has made me a convert).

    As always, great review and info!