Uni-ball Signo gel ink pens are known for their smooth writing and exceptional ink quality. And, to everyone's delight, there is a sea of colors and tip sizes to choose from. Find the perfect pen for any task, whether it's writing meticulous notes, marking your calendar, or decorating your scrapbook with colorful captions.

Everything about this pen, from its solid construction to its carefully-formulated ink, ensures a wonderful writing experience. The sturdy tip does not bend or break, even with heavy-handed use. The pigment-based ink flows smoothly and is waterproof, fade-resistant, and feather-resistant. Much of that is due to special viscous properties of the ink. The ink is viscous while in the barrel, but as it passes through the pen tip during writing, the viscosity drops. This results in smooth ink flow. Immediately after it hits the paper, the ink returns to its viscous state, which prevents feathering. You are left with beautiful clean lines that you can enjoy for a long time!

Model NumberUNI UM15105.24
Weight0.4 ounces
Body Color Clear
Body Material Plastic
Clip Material Plastic
Clippable Yes
Color Set No
Diameter - Grip 10.2 mm
Diameter - Max 10.2 mm
Grip Color Black
Grip Material Rubber
Ink Refillable Yes
Length - Capped 13.8 cm
Length - Posted 15.2 cm
Length - Uncapped 13.1 cm
Mechanism Capped
Pre-Installed Ink Color Black
Tip Length 4.3 mm
Tip Material Metal
Tip Size 0.5 mm
Tip Type Conical

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Customer Reviews

Excellent gel ink pen,...
April 28, 2013
Verified Purchase
Excellent gel ink pen, among the best and includes a rubber grip. Very good dark black color.
1 person found this helpful
ryoji kezu
Love these. Like others,...
July 29, 2009
Verified Purchase
Love these. Like others, I thought the Hi Tec .05mm was going to be my fave (writing and journal work for me) but this is the best yet. Very comfortable and great flow without being too heavy and no bleed through. Blue black is a wonderful color, I'll be trying the brown-black next!
1 person found this helpful
Just what I want...
February 4, 2015
Verified Purchase
Just what I want
Years ago when living...
December 3, 2014
Verified Purchase
Years ago when living in Kenya I enjoyed the Uni-ball Signo DX. I was not able to find them in the normal retail stores in the USA. Although the name has changed a little, the UM-151 is the exact same pen with the same quality. Nice even flow with permanent ink and feels right in the hand.
After hearing such great...
October 15, 2014
Verified Purchase
After hearing such great comments about this pen, I decided to check it out. I have to admit, I was a little disappointed when it started skipping sometimes and accumulating ink blobs on the tip occasionally. Also, the ink doesn't last too long if you're someone who is planning on using this pen to take notes every day; mine is almost out after about 3 months of regular note-taking. However, when it it writes well, the results are pretty awesome; dark, black ink and your hand feeling happy as it glides effortlessly across the paper. Bottom line is: if you're looking for a medium-to-bold gel pen for note-taking, this pen is right for you!