---
product_id: 23832779
title: "Uni Uni-Ball Signo Knock Ballpoint Pen RT1 0.28mm Color, Blue (UMN15528.33)"
brand: "三菱鉛筆"
price: "₨201"
currency: SCR
in_stock: true
reviews_count: 13
category: "三菱鉛筆"
url: https://www.desertcart.sc/products/23832779-uni-uni-ball-signo-knock-ballpoint-pen-rt1-0-28mm
store_origin: SC
region: Seychelles
---

# Vibrant blue ink 0.28mm super fine tip Precision Japanese engineering Uni Uni-Ball Signo Knock Ballpoint Pen RT1 0.28mm Color, Blue (UMN15528.33)

**Brand:** 三菱鉛筆
**Price:** ₨201
**Availability:** ✅ In Stock

## Summary

> 🖋️ Write sharp, stand out sharper.

## Quick Answers

- **What is this?** Uni Uni-Ball Signo Knock Ballpoint Pen RT1 0.28mm Color, Blue (UMN15528.33) by 三菱鉛筆
- **How much does it cost?** ₨201 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.sc](https://www.desertcart.sc/products/23832779-uni-uni-ball-signo-knock-ballpoint-pen-rt1-0-28mm)

## Best For

- 三菱鉛筆 enthusiasts

## Why This Product

- Trusted 三菱鉛筆 brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Vivid Blue Ink:** Make your notes pop with rich, eye-catching color.
- • **Crafted in Japan:** Trusted quality and reliability from a world-renowned pen maker.
- • **Featherlight at 0.16oz:** Comfortable for long meetings and brainstorming sessions.
- • **Retractable Convenience:** No cap, no hassle—just click and write.
- • **Ultra-Precise 0.28mm Tip:** Experience flawless, detailed writing with every stroke.

## Overview

The Uni Ball Signo Knock Ballpoint Pen RT1 features a super fine 0.28mm tip delivering precise, clean lines in vibrant blue ink. Designed with a retractable mechanism and weighing just 0.16 ounces, this pen combines convenience and comfort. Made in Japan, it embodies superior craftsmanship perfect for professionals who demand excellence in every word.

## Description

Uni Uni-Ball Signo Knock Ballpoint pen RT1 0.28mm Color, Blue

Review: So FINE!!! - You actually can write on a piece of rice!
Review: Favorite pen - This is my favorite pen I've ever owned. I like writing with very fine lines, and I was using the Staedtler fine point ballpoint pen before. While the description of this pen says ballpoint, it is in fact a rollerball, the difference being that ballpoint pens use a thick oil ink and rollerballs use a liquid ink. I prefer rollerballs because they are darker and smoother, and I find more consistent. The Staedtler pen I was using had previously been the thinnest pen I'd ever used, but because it was a ballpoint it just wasn't consistent, and they are like $10 a pop with no refills. The Uniball Signo RT1 series is much thinner, and because it's a rollerball, way darker and more consistent. I love it so, so much.

## Features

- Country of Origin : Japan
- Color ink Knock ballpoint pen
- The Package Height of the Product is 1.0 inches
- The Package Length of the Product is 1.0 inches

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Manufacturer | Uni |
| Brand | 三菱鉛筆 |
| Item Weight | 0.16 ounces |
| Item model number | UMN15528.33 |
| Is Discontinued By Manufacturer | No |
| Color | Blue |
| Closure | Retractable |
| Material Type | Plastic |
| Number of Items | 1 |
| Size | 1 Count (Pack of 1) |
| Point Type | Super Fine |
| Line Size | 0.3mm |
| Ink Color | Blue |
| Manufacturer Part Number | UMN15528.33 |

## Product Details

- **Brand:** 三菱鉛筆
- **Writing Instrument Form:** Ballpoint Pen
- **Color:** Blue
- **Ink Color:** Blue
- **Age Range (Description):** Adult

## Images

![Uni Uni-Ball Signo Knock Ballpoint Pen RT1 0.28mm Color, Blue (UMN15528.33) - Image 1](https://m.media-amazon.com/images/I/51IaPS208eL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ So FINE!!!
*by S***E on November 9, 2025*

You actually can write on a piece of rice!

### ⭐⭐⭐⭐⭐ Favorite pen
*by C***R on July 23, 2018*

This is my favorite pen I've ever owned. I like writing with very fine lines, and I was using the Staedtler fine point ballpoint pen before. While the description of this pen says ballpoint, it is in fact a rollerball, the difference being that ballpoint pens use a thick oil ink and rollerballs use a liquid ink. I prefer rollerballs because they are darker and smoother, and I find more consistent. The Staedtler pen I was using had previously been the thinnest pen I'd ever used, but because it was a ballpoint it just wasn't consistent, and they are like $10 a pop with no refills. The Uniball Signo RT1 series is much thinner, and because it's a rollerball, way darker and more consistent. I love it so, so much.

### ⭐⭐⭐⭐⭐ Best and finest I've found.
*by W***? on August 12, 2017*

The problem with trying to find the perfect fine point pen is that how fine it writes depends too much on the paper you're using as well as the technique. I spent too much money looking for the finest point writing tool I could find that would not bleed or smudge. Perhaps it's the fact that most fine point nibs are either fountain pens or felt tip- both of which tend to have very temperamental results. I've wasted money purchasing too many pens that claimed to be finer than this one, but for whatever reason (probably paper type) would often write in lines that were almost twice as thick as this one. It wasn't until I came across someone who claimed to me that this 0.28 nib pen actually wrote finer than many 0.1 nibs out there that I decided to give this a try and they were correct! I have pens that claim to be finer than this one and yet this one clearly writes much finer than they do without any bleeding or smudging. So I can write as tiny as I like without the compromises. I've now purchased a set of these with various colors, but since I can usually only travel with one pen- If they make a multicolor pen with 4 or 5 colors in one with a point this fine I will then truly be ecstatic.

## Frequently Bought Together

- Uni Ball Signo Knock Ballpoint Pen RT1 0.28mm Color, Blue (UMN15528.33)
- Uni-ball Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Rubber Grip, Black Ink, UMN-155-28, Value Set of 5
- Uni Japan Signo RT1 Retractable Gel Ink Pen, Ultra Micro Point 0.28mm, Renewal 2021 Rubber Grip, Blue Black 3 Pens With Kanji LOVE Sticker

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*Product available on Desertcart Seychelles*
*Store origin: SC*
*Last updated: 2026-02-07*