Uni-Ball

Uni-ball Signo RT1 Retractable Gel Ink Pen Ultra Micro Point 0 28mm Rubber Grip Black Ink UMN-155-28 Value

$9.99
sizeS

116+ bought in the past month

About this item

  • Uni-ball Signo RT1 Retractable Gel Ink Pen, UMN-155-28
  • The diameter of a lead : Ultra Micro Point 0.28mm, Color : Black Ink
  • Because there is no corner at the pen tip, it is not caught on paper, Smooth ink is also excellent in water resistance and light resistance
  • Value Pack of 5
$9.99

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Product details
BrandUni-Ball
Writing Instrument FormRoller Ball Pen
ColorBlack
Ink ColorBlack
Age Range (Description)Teen
Technical specifications
manufacturerUni-ball
brandUni-Ball
item_weight1.76 ounces
product_dimensions5.91 x 2.17 x 0.79 inches
item_model_numberSG_B06Y3S2XKL_US
is_discontinued_by_manufacturerNo
colorBlack
closureRetractable
grip_typerubber
material_typeRubber
number_of_items5
size1 Count (Pack of 5)
point_typeUltra Micro
line_size0.28 millimeters
ink_colorBlack
manufacturer_part_numberUMN15528.24*5
best_sellers_rank#4,858 in Office Products ( See Top 100 in Office Products ) #193 in Gel Ink Pens
date_first_availableApril 6, 2017

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Customer reviews

4.61,782 ratings
  1. 588%
  2. 413%
  3. 30%
  4. 20%
  5. 10%

Customers say

Customers find these pens excellent for writing in Bibles and technical work, with a super fine point and perfect thickness.

★★★★★

Fantastic!

K. H.June 25, 2024✓ Verified purchase

This pen is fantastic! It writes smoothly, doesn't scratch the paper, and makes the thinnest lines that I've ever seen in a writing pen while still being dark enough to easily read. Some art pens are comparable, but are not really meant for continuous writing like you can with these. I use the pens to fill out care plans and med cards in nursing school and they work nearly perfectly for pages of writing. Recently, only one of the pens that I have been using frequently started skipping slightly even though there's still a decent amount of ink in the pen. Other than that, they have been perfect, especially because the grip/soft area continues to the tip and is comfortable to write with continuously. I've never loved a pen like I love these pens. I'd rate them 9.99 out of 10 (0.01 taken away for the one pen out of the 5 that skips after writing for a while). Read more

★★★★★

Work great!

KS26January 19, 2023✓ Verified purchase

I'm one of those people who has an unusual obsession with office supplies. As such, I have tried numerous pens in hopes of finding the ~perfect~ pen to use in my everyday life. These are not the ~perfect~ pen; however, they are pretty great regardless. They are comfortable to hold and use thanks to the rubber grip, and the tips are SUPER fine as promised. After using Micron pens for the first time, I found that I favor pens in the .25-.4mm range for writing as the lines are finer and cleaner, and these definitely meet that expectation. So far, I haven't had any issues with bleeding, smearing, skipping, etc. I think it's because the ink comes out so thin, it dries before it even has a chance to smear; but then, I'm also right-handed, so unless I'm especially careless, I don't have many opportunities to smear my writing. I will say that, because the lines obviously come out thinner and therefore somewhat lighter than .5+ pens, people with poor eyesight may struggle to read things written with these .28mm pens, but I wear glasses so it doesn't bother me. Price wise, I think that these are a good deal. They cost about the same amount as the Papermate InkJoy gel pens and Tul gel pens I've been using, but you get more in a pack and the quality is great. Plus, anything finer than .5mm is frustratingly hard to come by. I definitely recommend giving these a try. Read more

★★★★★

Very fine point!

SamanthaMay 30, 2025✓ Verified purchase

I LOVE THESE PENS!! This is exactly what I was looking for! I'm using them in my planner and journaling. The writing is smooth and very fine but I can still see the blank ink. Definitely gonna get more when I run out. I'll see how long they last but so far they are great! I'm not sure about the price but seems reasonable to me. Read more

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★★★★★

Great pen.

Brett BartelsFebruary 11, 2026✓ Verified purchase

These are a hit in my clinic. We love a fine tip that doesn’t bleed. Read more

★★★★☆

Writes Easily. Also Clogs Easily.

David FinleyOctober 16, 2025✓ Verified purchase

TLDR: crisp, smudge free, fine writing BUT clogs way too easily For context, I normally use FRIXION synergy knock 0.38 erasable pens or the Pentel Energel fine tip pens. I work in healthcare and like that the FRIXION pens are erasable, but they are not very concentrated in color. I like the Energel pens, but they smudge very easily. I was excited to try this pen because I heard great things about it. I normally like thin pens, so this was one that I have been wanting to try. When I first wrote with it, it was beautiful. Super fine lines, very crisp, and very good smudge resistance. If it stayed like this, I would’ve said it was my new favorite pen! It is very lightweight and comfortable to write with. However, it clogs way too easily. I think it was within 2 to 3 days that my first pen clogged up with no valid rhyme or reason. I tried soaking it in hot water. I tried multiple troubleshooting mechanisms, but nothing seemed to get it back to its normal writing capacity. I opened up another pen and within a week it did the same thing. I thought it might have been the notepad I was writing on for some reason, but even after changing notebooks, I noticed the same problem. It is very frustrating to have gone through two pens of this five pack in less than two weeks. Hopefully it was just a defective batch and I’ll probably try to order it again in the future but for now it doesn’t meet my expectations. Super disappointed since it writes so beautifully. I included a picture of what the dead pen was writing like. I had thrown the pen away after it died on me during my shift so I wasn’t able to show the comparison on the bottom. For reference, I included the other two pens I usually write with so there’s a visual comparison of what a brand new pen writes like. Read more

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★★★★★

Great for medical use

nonyadamnbiznesApril 12, 2025✓ Verified purchase

Amazing pen if you need to write small and still be able to read it. I work as an intensivist in a busy MICU and of the substantial number of pens I've used over the years these are by far the best for small detail dense writing. I like to keep a single sheet of paper with me for my patient list and having the ability to pack everything I need to keep track of in a small section of the page only really works with these pens. I have tried 0.25mm pens however they either write too faint or actually cut the paper, something that has never been an issue with these 0.28mm pens. Plus the gel ink dries quickly, the pen head glides easily over the page, and the stock pen body is comfortable in hand. A very good value of a pen that out classes ones costing ten times as much. Read more

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★★★★★

Thin tip makes for smooth writing

Patricia MooreDecember 15, 2025✓ Verified purchase

Writes great, love the thin tip. Read more

★★★★★

perfect for sketching

howstheskyOctober 19, 2025✓ Verified purchase

I just started urban sketching on location and needed a no-fuss pen (always works, quick drying, no pen caps to lose). This pen is perfect. The click mechanism is why I'm using this pen vs my usual Micron pens. Ink flow is very consistent across various angles. The grip is nice, not slippery when wet. Read more

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