---
product_id: 43706154
title: "Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5"
brand: "uni-ball"
price: "¥3116"
currency: JPY
in_stock: true
reviews_count: 13
category: "Uni Ball"
url: https://www.desertcart.jp/products/43706154-signo-rt1-retractable-gel-ink-pen-ultra-micro-point-0
store_origin: JP
region: Japan
---

# Ergonomic rubber grip for all-day comfort Smooth, water & light resistant gel ink 0.28mm Ultra Micro Point Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5

**Brand:** uni-ball
**Price:** ¥3116
**Availability:** ✅ In Stock

## Summary

> 🖋️ Write sharp, write smart — the pen that means business.

## Quick Answers

- **What is this?** Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5 by uni-ball
- **How much does it cost?** ¥3116 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/43706154-signo-rt1-retractable-gel-ink-pen-ultra-micro-point-0)

## Best For

- uni-ball enthusiasts

## Why This Product

- Trusted uni-ball brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Ready When You Are:** Retractable design means no caps to lose—just smooth, instant writing whenever inspiration strikes.
- • **Comfort Meets Control:** Soft rubber grip extends to the tip, providing fatigue-free writing even during marathon meetings or study sessions.
- • **Precision in Every Stroke:** Ultra-fine 0.28mm tip delivers the sharpest, cleanest lines for detailed writing and note-taking.
- • **Ink That Lasts and Impresses:** Waterproof and fade-resistant gel ink ensures your work stays vibrant and professional under any condition.
- • **Value Pack for the Go-Getter:** Set of 5 pens keeps you stocked and ready, so you never run out during your busiest days.

## Overview

The Uni-ball Signo RT1 is a premium retractable gel ink pen featuring an ultra micro 0.28mm tip for ultra-precise writing. Its smooth, water- and light-resistant black gel ink ensures durability and clarity, while the ergonomic rubber grip offers superior comfort for extended use. Sold in a convenient value pack of 5, this pen is perfect for professionals and students who demand reliability and finesse in every line.

## Description

Uni-ball Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Black Ink, UMN-155-28, Value Set of 5

Review: Quality precision pens - I’m used to the Zebra Sarasa 0.3 mm, which is my go to pen, and wanted to find something of comparable quality with an even finer tip, to allow for smaller writing that’s still clear. Uni-ball Signo was at the top of the list of many pen reviewers so gave this 0.28 model a try. It’s checking all the boxes - smooth ink flow, micro thin lines, but not scratchy thin. Great value, nice clip, so far so good.
Review: Great pen - Great pen. Writes great, smooth, and dries fast. Interesting choice of the package though

## Features

- 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

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B06Y3S2XKL |
| Age Range (Description) | Teen |
| Age Range Description | Teen |
| Best Sellers Rank | #5,809 in Office Products ( See Top 100 in Office Products ) #205 in Gel Ink Pens |
| Body Shape | Round |
| Brand | Uni-Ball |
| Brand Name | Uni-Ball |
| Closure Type | Retractable |
| Color | Black |
| Customer Reviews | 4.6 out of 5 stars 1,819 Reviews |
| Drill Point | Ultra Micro |
| Grip Type | rubber |
| Hand Orientation | Ambidextrous |
| Ink Base | Water |
| Ink Color | Black |
| Item Dimensions | 5.91 x 2.17 x 0.79 inches |
| Item Weight | 2.08 ounces |
| Line Size | 0.28 millimeters |
| Manufacturer | Uni-ball |
| Material | Rubber |
| Material Type | Rubber |
| Model Name | ball point pen |
| Model Number | SG_B06Y3S2XKL_US |
| UPC | 191308002770 |
| Unit Count | 5 Count |
| Water Resistance Level | Water Resistant |
| Writing Instrument Form | Roller Ball Pen |
| Writing Technique | gel ink |

## Product Details

- **Age Range (Description):** Teen
- **Brand:** Uni-Ball
- **Color:** Black
- **Ink Color:** Black
- **Writing Instrument Form:** Roller Ball Pen

## Images

![Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5 - Image 1](https://m.media-amazon.com/images/I/41G6JyrC6SL.jpg)
![Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5 - Image 2](https://m.media-amazon.com/images/I/41-dQgHq8mL.jpg)
![Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5 - Image 3](https://m.media-amazon.com/images/I/31iKhNcnK2L.jpg)
![Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5 - Image 4](https://m.media-amazon.com/images/I/31ro8xs9S0L.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Quality precision pens
*by M***Y on April 27, 2026*

I’m used to the Zebra Sarasa 0.3 mm, which is my go to pen, and wanted to find something of comparable quality with an even finer tip, to allow for smaller writing that’s still clear. Uni-ball Signo was at the top of the list of many pen reviewers so gave this 0.28 model a try. It’s checking all the boxes - smooth ink flow, micro thin lines, but not scratchy thin. Great value, nice clip, so far so good.

### ⭐⭐⭐⭐⭐ Great pen
*by H***I on April 7, 2026*

Great pen. Writes great, smooth, and dries fast. Interesting choice of the package though

### ⭐⭐⭐⭐⭐ Great pens
*by M***L on April 2, 2026*

Great pens. I love the fine point. They do run out of ink pretty fast. I go through about 1 per week but I just keep a stash on hand.

## Frequently Bought Together

- Uni-ball Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5
- UPENOTE Gel Pens 0.28mm Extra Fine Point Pen, Black Ink, Ball Point Pen for School, Office, Stationery Supplies 6 Packs
- Uni-ball Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, UMN-155-28, 10 Color Value Set

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-05-20*