Pens and Pencils | Reviews and Data

Uni-ball Signo UM-151 Gel Pen

Uni UM-151

The Uni-ball Signo DX UM-151 is capped (stick style) gel pen that is sold in a huge variety of colors. It’s sold as single pens, but also often sold in bundles that can have many pens and many colors.

The key features of the pen are a dimpled rubber grip on a plastic body, and a steel tip at the front. The defining feature is the vibrant pigment-based ink that bonds permanently with paper, making the pen excellent for writing checks but also for painting and other artistic pursuits.

In the United States this pen is sold as the Uni-ball Gel Grip, in Japan it’s the Uni Signo DX, with the model number of UM-151.

Then pen is sold in at least 20 colors (depending on your region) as well as metallic colors, pastels, and others. It’s popularly seen in 0.5 mm and 0.7 mm sizes, but also sold in 0.28 mm and 0.38 mm.

Uni-Ball Signo DX (UM-151) Gel Pen Review

The Uni-Ball Signo Dx is a simple stick gel pen the works well and is an excellent value. The design is simple, sleek, and effective. The pen is all plastic except for the metal cone piece. The plastic cap will post.

The pen is very light but feels good. The metal cone adds weight to the tip to give good balance and control. The pen is also a great length. Unposted, it sits about an inch above the top of my grip. The clear body is nice so you can see ink levels but isn’t too exciting.

The dimpled rubber grip is also a nice touch over other simple stick gel pens. It does a good job of improving comfort for short and log writing sessions. The clip feels a little flimsy but shouldn’t break under normal use.

Writing Experience

The Signo UM-151 (aka Signo DX) is a solid writer thanks to the UMR-1 refill inside. It’s quite smooth but may have some feedback in the smaller tip sizes, especially on more textured papers. The gel ink is an excellent performer and has very nice color saturation.

The ink is not the fastest drying but is no slouch. After about 5 seconds its dry enough to not smear or smudge. The ink is also pigment-based, archival quality, fade resistant, and acid-free.

Note-taking with this pen is very pleasurable. Extended writing sessions are no problem and hand fatigue is minimal. I would have no reservations taking this pen to a 3-hour meeting and making notes the whole time. The rubber grip also does a good job with sweaty hands.


The Signo DX is a top pick of mine as cheap pens go. It’s a no non-sense pen that puts down ink reliably. It may not be the most interesting pen, or the coolest looking, but it does its job very well.

For about $3 a pen, the price is also hard to argue with. If you need a simple and affordable gel pen, the Uni-ball Signo DX is a top choice.

Other similar pens would be Pilot Hi-Tec-C, the Zebra Sarasa Push Clip, and the Pentel Energel. All which are great pens and good alternative choices. I prefer the Zebra Sarasa pens, but you can’t go wrong with Signo DX. It’s a great pen at a great price!

Uni-ball Signo UM-151 Gel Pen Information

Street Price Check Price
Manufacturer Uni
Pen Type Rollerball / Gel
Barrel Color Clear
Barrel Material Plastic
Body Diameter (mm)10.3 mm
Grip Color Brown, Purple, Silver, Light Brown, Light Blue, Light Pink, Gold, Bronze, Red, Orange, Blue, Pink, White, Yellow, Light Green, Lime Green, Baby Pink, Metallic Red, Pure Pink, Sky Blue, Pastel Yellow, Pink, Metallic Silver, Metallic Blue, Light Blue, Light Green, Silver, Gold, White, Pink, Gray, Red, Yellow, Bronze, Black, Dark Blue, Blue, Purple, Orange, Light Brown, Green, Brown, Green, Purple, Gold, Orange, Bronze, Yellow, Light Green
Grip Material Rubber
Grip Diameter (mm)10.3 mm
Country of Origin Japan
MSRP $2.55
Still Sold Yes
Similar To
Capped? Retractable?Capped - Snap On
Length Capped / Retracted (cm)13.8
Length Posted (cm)15.3 cm
Length Uncapped (cm)13.1 cm
Weight (g)11 grams
Ink Color ShippedPink, Metallic Pink, Silver, Light Brown (Khaki), Purple, Gold (Metallic Gold), Baby Pink, Golden Yellow, Sky Blue, Red, Brown Black, White, Violet, Green (Metallic Green), Light Green (Apple Green), Bronze (Metallic Bronze), Light Brown (Beige), Pure Pink, Orange, Light Blue, Yellow, Blue (Metallic Blue), Purple (Metallic Violet), Red (Metallic Red), Green (Metallic Green), Gray (Grey), Brown Black, Turquoise (Blue Green), Purple (Lilac), Gray (Dark Grey), Green, Emerald Green, Pink (Pastel Red), Blue Black, Dark Blue (Prussian Blue), Black, Orange (Pastel Orange), Light Green (Pastel Green), Red (Metallic Red), Bronze (Metallic Bronze), Mandarin Orange, Pink, Light Blue (Pastel Blue), Blue, Gold (Metallic Gold), Purple (Pastel Violet), Yellow (Pastel Yellow), Brown, Violet, Purple (Metallic Violet), White, Pink (Pastel Pink), Red, Blue (Metallic Blue), Lime Green, Light Brown (Khaki), Pink (Metallic Pink), Silver (Metallic Silver), Green, Purple (Metallic Violet), Emerald Green, Gold (Metallic Gold), Lime Green, Bronze (Metallic Bronze), Golden Yellow, Orange
Writing Sizes0.28 mm, 0.38 mm, 0.5 mm, 0.7 mm