Uni-ball Signo UM-151 Revisiting an Old Favorite

Uni-ball Signo UM-151 Color Samples

Uni-ball Signo UM-151 Color Samples

I have reviewed many color and size combinations of the popular Uni-ball Signo UM-151 which also used to be called the Signo DX, but recently realized that its been a while since I really put them to use.  These were an early favorite that I discovered from reading some of Brad’s great reviews of them so I decided it was time to re-establish them as a go-to option for daily use.

Uni-ball Signo UM-151 Tip Comparison

Uni-ball Signo UM-151 Tip Comparison – Left is the .38mm Right is the .28mm

The Uni-ball Signo UM-151 comes in a huge variety of colors and are available in two of my favorite tip sizes, .28mm and .38mm.  Personally I don’t mind the somewhat scratchy feel that you get with the .28mm version of the Uni-ball Signo UM-151, but the .38mm is actually pretty smooth for such a small tipped pen.  I tend to use the .38mm versions for some daily note taking and the .28mm versions usually end up as my editing and updating pens for when I have to squeeze in some small handwriting to existing notes to clarify or update something.    I use the .38mm version for daily notes in some recurring weekly meetings that I run, and the notes just run along a chronological stream in one of my Levenger Circa notebooks.  Each week when I start a new section of notes after the previous week’s notes, in a new color, its a great way to help differentiate and also remember where things are in the notes for later reference.  The bright bold colors and the wide variety that they come in help make notes more memorable for me, so that is a big win from a work and organizational perspective.

Uniball Signo UM-151 Body

Uniball Signo UM-151 Body

Forgive me for the older picture from an earlier review of the pen, but the Uni-ball Signo UM-151 body remains the same with some minor differences in the branding and markings on the pen which are now done via removable stickers, which I prefer.  Overall though the bodies on these pens are perfect because they are quite durable and they are transparent so you can see how much ink you have left in he refill.  They also have a no non-sense comfortable grip that makes them great for every day and frequent use.  One minor issue I have always had is the tiny caps on these pens.    This is just more of a style preference for me, it doesn’t change the performance of the pen, but I’ve noticed that I tend to drop these caps and misplace them more often than caps for my other pens.

Uni-ball Signo UM-151 Clips

Uni-ball Signo UM-151 Clips

Speaking of the clips on the Uni-ball Signo UM-151 here is a quick look at them so you can see the main difference between the .38mm and .28mm version of this pen.  The 28mm cap has a clip that matches the pens color, but is translucent as compared to the .8mm version that has a solid (yet still color matched) clip.  Again, not a big deal, but definitely helpful in quickly identifying which version you are grabbing for if you have multiple versions of these in your pen case as I do.

Uni-ball Signo UM-151 Summary

For a few weeks now I’ve really been enjoying and getting benefit out of making the Uni-ball Signo UM-151 a regular part of my rotation again.  The huge variety of colors, multiple tip sizes, and great construction make these pens a great all round option for so may different purposes.  If you have not tried them, or like me have neglected them recently I highly recommend getting back in the game with them, JetPens has the biggest selection I’ve seen and also has the .5mm versions, while Amazon also has some available.  Regardless of where you get them, I hope you give them a chance and enjoy them as much as I have been.

©2015, Brian Greene. All rights reserved.


  1. 1
    Iris says:

    My preference in this range is the Signo Gel RT or Signo RT1 in 0.38 or 0.28 points, so I don’t have to mess with the caps. Unfortunately, the transparent barrel letting you see how much is ink is left fails when you get down to the nitty gritty end, being obscured by the grip. I wouldn’t want to give up the grip, but I end up unscrewing the tip to check the ink left near the end. The Signo RT Gel has a clear, uncolored barrel, but the RT1 barrels are tinted. And some of the RT1 colors have opaque bodies.

    One would think the retractable version would be refillable, but the refills, when they can be found, cost more than buying these by the dozen. Since they’re my everyday pen, I generally just buy the box when I buy black. At work, I have our admin order me a box of black ones about every 8 months or so.

  2. 2
    Brian Greene says:

    @Iris – Thats some great feedback and I completely agree on the Signo Gel RT in the .38, I love that pen…just wish it came in the range of colors that the UM-151 comes in. Good point about the grip and ink level…although when it gets that low you know you are getting pretty close. :)

    I’m with you on that frustration around the refills costing more than some of the pens. I did some analysis on that a while back and identified some good and bad pens in that department:


  3. 3
    Cary T. says:

    These and Hi-Tec-C are the only gel pens I now use thanks to shifting over to fountain pens. I only use 0.38 as I like a fine pen but 0.28 is a bit too fine for a pen of this caliber (at least for me). For thinner, I use Microns.

  4. 4
    Brian Greene says:

    @Cary T. – The Hi-Tec-C is definitely another great option. I’ve tried Microns before, but never really used them extensively, maybe I should give them a try….thanks for the feedback!

  5. 5
    jessie says:

    I recently purchased a few of the Signo 0.38 in various colors and encountered a weird issue. I’ll be writing fine with it then the ink will start to diminish and then all of a sudden I find a huge blob of ink at the end of my tip. I’ll wipe it off and then try again, and the same process happens maybe 3 minutes later. I’ve tried this with about 3 or 4 different colors and they all did they same thing. Has anyone else experienced this issue with the Signos lately?

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