The Jetstream Is THAT Good: Hands on with the Uni M17 Lamy Refill

It baffles me why Uni’s Jetstream Ink still hasn’t caught on as the default ballpoint pen ink outside of Japan. For those not in the know, the Uni Jetstream is the original “hybrid gel” or “low viscosity” ballpoint pen, which combines the smoothness of a gel pen with the write-anywhere capability and quick-dry features of a standard ballpoint. For me, the Jetstream has everything you would want in a refill: It writes a dark, solid line. It flows well. It dries nearly instantaneously and does not smear. Importantly, it works reliably in a range of tip sizes, from .38mm all the way up to 1.0mm. Yet we are still largely forced to import pretty much everything other than standard disposable Jetstreams click pens from Japan, despite Uni manufacturing a multitude of different refill formats that fit not just Uni pens but third-party brands.

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I have new and vintage Lamy ballpoints, and the M17 refill works well in both of them. Shown here is the Lamy Unic (“Unicorn”? - now discontinued), as well as a standard Safari.

The much-publicized, Japan-only 2025 release of the Uni Jetstream M17 ballpoint refill - designed to fit M16-compatible Lamy pens, merely reinforces the absurdity of this situation. Look, I don’t mind the standard Lamy M16 ballpoint refill. There may have been some spotty QC years ago, and the current version is quite good, but it remains a standard ballpoint writing experience that’s never going to rise above the limitations of that technology. By adding the Jetstream ink, the M17 refill improves the writing experience significantly. But as with other Jetstream formats, there’s still no indication that this refill will be consistently available to markets outside of Japan. In the Japanese market, retailers now have a Safari Ballpoint option with “Jetstream Inside”, i.e. the Jetstream refill is included with the pen. Yeah, that probably won’t happen here. But I hope I’m wrong. :)

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Many love the black Jetstream refills for their solid black line.

Takeaways and Where to Buy

I won’t beat the Jetstream drum any more than I already have. I especially love the Jetstream Multi Pens - mainly because they’re the way to get colors other than black - and Uni recently released an even smoother Jetstream ink (the “Lite Touch”) that some believe outperforms the original formulation. Most of my personal pens that take Parker-style refills now use the SXR-600, and my Lamy 2000 Multi Pen (4-Color Ballpoint) has long held the SXR-200 D1 refills. I’m a bit worried about falling too hard for the M17, because I don’t know how stable the supply will be given the current trade situation, but for right now I’m going to enjoy what I have. If you’re a Lamy fan and want to up your ballpoint game, grab some of them if you have the opportunity.

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Only one part of our Jetstream selection!

Our store carries a wide variety of Jetstream pens as well as refills in as many formats as we are able to source. We still have a few Uni M17 refills in stock from the small shipment I managed to source. (Update: These are now sold out.) I'll try to find more, but timing of a resupply is uncertain at best. Stay tuned!

If you’re ever in the Nashville, Tennessee area, please stop in and see us! We’d love to welcome you in store and answer any questions you may have. The Gentleman Stationer is open this week Thursday (1-4) and Friday (1-6) and Saturday from 10-4. Our site is entirely self-supported through the shop and the T.G.S. Patreon Program.

Comparing Low Viscosity Ballpoint Pens: Jetstream vs. Acroball vs. Anterique vs. Ohto

It’s been interesting to see pen manufacturers - especially the Japanese manufacturers - move away from standard ballpoints to low viscosity refills. You sometimes hear these refills referred to as “hybrid gel-ballpoint”, because they combine the permanence and quick dry times of a classic ballpoint pen with the smoothness of a gel pen. Personally, I love them, and they form a core part of my own everyday writing rotation. The downside is that outside the Jetstream line, you don’t have many color options, with most companies offering these refills only in black.

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In order of darkness, I would rank the inks as follows: Pilot Acro Ink, Uni Jetstream, Anterique Mach Ball, and Ohto. In order of dry time, I would rank them the exact inverse: Ohto, Anterique Mach Ball, Uni Jetstream, and Pilot Acro Ink. That’s not to say that any of them “dry slowly,” but with a darker like, you will get more smoothness, and with that added smoothness comes increased dry time because it means more ink is on the page.

With so many of these sorts of pens entering the market, I thought it might be helpful to do a quick comparison of my thoughts on four of the most common brands: Pilot (Acro-Ink / Acroball), Uni (Jetstream), Ohto (various needle-tip refills), and Anterique (“Mach-ball”). See below for my thoughts on each. Please note that this post is not intended to be comprehensive, but rather an overview of the more popular refills that I often get asked about, with a focus on how they compare to one another. For a more general overview of low-viscosity ballpoints, including other brands, see this post here.

• Uni Jetstream. Probably the easiest to find of all the refills featured in this post, the Jetstream comes in anything from D1 size to Uni’s own proprietary multi-pen size to a standard Parker-style cartridge. The biggest selling point of the Jetstream is the number of options you have. D1 and multi pen refills come in colors that include black, blue, red, and green, and even though the Parker-style cartridges are available only in black, you still have .38mm, .5mm, and .7mm tip sizes. Jetstreams are smooth writers - maybe not quite as smooth as Pilot’s Acro-ink, but you’d have to be a pretty big ballpoint aficionado to notice the difference.

• Pilot Acro-Ink. In my opinion, the smoothest, easiest-writing refill on this list. While Pilot’s Acro-Ink refills aren’t quite as ubiquitous as the Jetstream line, I like them for longer-form writing. The .7mm writes a smooth line without smearing, and in my opinion it’s a better .7mm tip size than the Jetstream. These refills are found in the Pilot S20 ballpoints, the “Dr. Grip” line, and the Pilot “Acroball” pens that you can sometimes find in larger office supply stores.

• Anterique “Mach Ball” Refill. Anterique is known for taking the classic vintage-style click pen and upgrading it with their excellent refill. It only comes in one tip size (.5mm), with black ink, but it’s a great pen and relatively inexpensive. Pro tip: you can often substitute one of these refills into a standard vintage Bic Clic ballpoint. I have a large collection of vintage ballpoint pens, and it’s been a joy to give many of them a fresh life with a new refill. Sometimes you have to trim or extend the Anterique refill, as I don’t think the specs on the Clic were consistent over the years, but there are only a couple of exceptions where I was unable to make it work. Anterique’s biggest selling point is that it dries nearly instantaneously.

• Ohto Needle-Tip Ballpoint Refill. The ultra-precise .5mm needle-tip ballpoint has become Ohto’s hallmark. Of all the pens on this page, Ohto’s are on the drier side, but what this means is that you will get a very precise line and zero smearing. Ohto makes the refill for Object Index, Traveler’s Company, and Mark’style branded pens. Honestly, if you see any Japanese needle-tip ballpoint pen, chances are it’s an Ohto.

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Writing sample pens are, from left, the Pilot S20 (shown here in brown), the Anterique Mach Ball Standard Size, the Object Index Cedar Pen, and the Uni Jetstream 4+1 Bamboo.

I’m a huge fan of ballpoints and they play a huge role in my everyday working life because, well, they just work. We stock a wide variety in our shop, and if you come visit us in person, ask to try each of the refills featured here, as we have testers generally available.

Thank you for reading! The Gentleman Stationer is supported by the T.G.S. Curated Shop and the T.G.S. Patreon Program. If you’d like to visit our in-person location, you can view directions and up-to-date hours here.

Workhorse Pens: Pilot S20 Ballpoint

The T.G.S. “Workhorse Pen” series is where I park all of my recommendations for those pens that I personally rely on to get work done. While this series started out as exclusively focused on fountain pens, as my interests have become more eclectic over the years, I’ve expanded the series to cover other categories - namely low-viscosity ballpoint pens.

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While the low-viscosity ballpoint pen received its own writeup as a category, I wanted to take a moment to highlight an exceptionally good take on the product: the Pilot S20 ballpoint pen. The S20 has been around for a while, in both ballpoint and mechanical pencil format, though like many of Pilot’s best products, distribution has been largely limited to Japan. Featuring Pilot’s “Acro-ink” (the Acroball refill in a Dr. Grip-style cartridge), the S20 stands out due to its unique shape and feel in addition to the excellent writing experience.

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Four different low-viscosity ballpoint pens (well, almost) that I use regularly. From left: Pilot S20, Uni Jetstream 4+1, Anterique Mach Ball in Clear Green, and the Caran d’Ache Infinite 888, which is not technically a low-viscosity ballpoint but has an exceptionally good refill. .

I won’t belabor the benefits of low-viscosity ballpoint ink, because they aren’t necessarily specific to the S20 and I’ve already written about them fairly extensively. To briefly recap, low-viscosity ballpoints are sometimes referred to as “hybrid gel” pens, meaning that they feature smoother ink flow than your typical oil-based ballpoint, while maintaining the faster dry times and increased permanence. The downside? Color selection. I’ve not seen many hybrid ballpoint pens come in colors other than black or blue (and sometimes red and green), as opposed to gel pens, which these days are available in pretty much any color you can think of.

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The combination of the gently shaped section and the tactile wood used in the Pilot S20 make for one of the most “usable” pens I’ve experienced. It’s honestly the first pen in a while that just makes me want to pick it up.

Why do I love the Pilot S20 so much? For starters, both the top and bottom halves of the pen feature a concave hourglass shape, which allows it to rest comfortably in my hand. While “feel”, “balance”, and “comfort” are highly subjective, in that they often depend on variables like hand size and writing pressure, I personally consider this one near perfect. The wood barrel gives the pen a tactile feel, making it one of those pens that’s a pleasure to pick up simply because it feels elegant - almost extravagant - despite only costing $25.

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The Dr. Grip “Cocoon” refill.

As for Pilot’s “Acro-ink”, to me this refill feels more gel-like than the Uni Jetstream or the Anterique Mach-ball refills, which have a more tactile feel akin to a pencil. Part of this might be that the S20 comes in a .7mm tip size, but I’ve always felt that Pilot Acroball pens lay down a darker, wetter line than their counterparts. This pen is a very smooth writer, so much that I’ve recently started using it for journaling - something I can’t say about other ballpoints in my rotation.

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Takeaways and Where to Buy

Since I got my hands on the S20 last year, I’ve not taken it out of my personal rotation. The red and black version sits in my Plotter A5 pen loop, and has become an everyday planner pen for me. The brown and black version lives on my writing desk at home. While the Dr. Grip is marketed as Pilot’s “ergonomic” everyday pen, I tend to find it slightly too large. The S20 better fits my own hand and writing style, while keeping the same excellent refill.

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For writing samples, I used standard Target-brand copy paper, since that is how many people have to use their ballpoints at work, school, and otherwise out in the world. Of the three shown here, I think the Pilot Acroball ink is the darkest, followed by the Anterique Mach Ball, and then the Jetstream. All are very good and I use them interchangeably.

As of this week, we have the Pilot S20 ballpoints back in stock in our shop. We sold through our initial shipment around Christmas, but have plenty once again. A few of you have asked about the mechanical pencil version, and the .5mm is on the way as soon as our supplier has it back in stock. (.3mm will depend on interest, so let us know!) The S20 ballpoint is priced at $25 and comes in two colors: Red/Black and Brown/Black. Additional refills are also available. I’ve checked, and these are indeed the same cartridges that fit the Dr. Grip pens sold here in the states, though these are .7mm “Fine” refills whereas most U.S. Dr. Grip pens are sold with the 1.0mm “Medium”. Personally, I prefer the fine, and will likely try to swap one into my Dr. Grip Full Black to see if it gets more use.

Thank you for reading! The Gentleman Stationer is supported by the T.G.S. Curated Shop and the T.G.S. Patreon Program. If you’d like to visit our in-person location, you can view directions and up-to-date hours here.

Pen Review: Object Index Cedar Pocket Pen

If today’s pen looks somewhat familiar, it’s because Object Index has released a pocket-sized take on the Mark’style Tous Les Jours Needle-tip ballpoint, and both feature different versions of the same excellent low-viscosity ballpoint refill. I love these pens because (1) they write a very fine .5mm line that dries almost instantly, with zero smearing; and (2) the hexagonal cedar barrels convincingly imitate the feel of a woodcase pencil.

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Though “pocket-sized,” the pen is still long enough to feel balanced - sort of like when woodcase pencils reach that “perfect” length, having been sharpened several times.

Object Index is a Kakimori “sibling brand” that recently arrived in the shop. The Object Index line includes pens, pencils, and various office and desk accessories, all with a shared minimalist design and complementary colors that include grey, yellow, and natural wood tones. Their take on these “woodcase pens” is a bit more understated than the Mark’s version, with minimal branding and a brushed metal nose cone and knock. The knock feels slightly upgraded on the Cedar Pocket Pen, with more resistance and a firmer feel.

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The signature needle tip of the Ohto refill.

While marketed as a “pocket pen,” I probably won’t be carrying this one in my actual pants pocket, as it’s wood and therefore more subject to damage than a heavier duty metal pen. That said, it’s quite slim, and will fit easily into the pen holders integrated into pocket notebook covers, Plotters, and more, which makes it portable. I understand that this particular pen is also designed to fit into a notepad made by Object Index, which I may try to get in the future.

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Each pen ships with two extra refills, in addition to the one in the barrel.

These needle-tip ballpoints use refills made by Ohto, another Japanese company that makes some of the best needle-tip ballpoint and gel refills around. As I mentioned, it uses a low-viscosity ink that behaves similar to a Uniball Jetstream. Each pen comes as part of a set, which includes three refills (one in the pen, two extra in the package) and is priced at $15 and available in three colors: Grey (shown here), as well as Yellow and Natural. We also have additional refills for this pen available once you use up the three included in the pack (though this will likely take you a VERY long time). For everyday writing, these pens can’t be beat, and many thanks to Kakimori for including an extra in my shipment so that I could review it and test it out myself.

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.5mm Needle-tip writing sample on Midori MD Memo Block paper.

The Gentleman Stationer is supported by purchases from the T.G.S. Curated Shop and pledges via the T.G.S. Patreon Program.