Uni-ball One 3 Multi-Colour Gel Pen

Three Colours. One Pen. Japan's Most Stylish Multi-Colour Gel Pen.

Introducing the Uni-ball One 3 Multi-Colour Gel Pen, a compact and beautifully designed 3-in-1 writing tool from Mitsubishi Pencil. It houses three independent gel ink refills—Black, Red, and Blue—in a single slim pen body, switchable instantly with an intuitive side selector mechanism.

Filled with Uni's signature Koi Iro (concentrated color) gel ink, it delivers vivid, saturated, and fast-drying lines that resist feathering. Compact enough to clip securely to an A5 notebook but stylish enough to leave on your desk, it is available in a curated range of matte-finished bodies.

✦ Key Features

• 3-in-1 multi-colour design — includes Black, Red, and Blue gel ink
• Koi Iro concentrated ink — noticeably more vivid and saturated than standard gel
• Intuitive side selector — switch colors instantly with a smooth, satisfying click
• Compact mini body — shorter and slimmer, perfect for notebook carrying
• Authentic Japanese import — genuine Mitsubishi Pencil quality and packaging

✦ Specifications

• Tip Options: 0.38mm (Fine) and 0.5mm (Medium)
• Ink Colors: Black, Red, Blue (All-in-one)
• Mechanism: Retractable Side-Selector
• Brand: Uni-ball (Mitsubishi Pencil)

Frequently Asked Questions

Q: What makes the "Koi Iro" ink different?

A: Koi Iro translates to concentrated color. Uni's proprietary formula uses larger pigment particles that sit on top of the paper rather than soaking in, resulting in a significantly darker, brighter, and more vivid line that resists feathering.

Q: Is the pen heavy or bulky?

A: Not at all! The Uni-ball One 3 was specifically designed to be compact and slightly shorter than standard multi-pens, making it slim enough to clip seamlessly to the cover of a notebook without adding bulk.

Q: Do I need to buy different refills for each color?

A: This pen houses all three colors (Black, Red, Blue) simultaneously. When one runs out, you can replace just that specific color cartridge using standard Uni-ball multi-pen refills.