Uni-ball One 3 Review: Three 0.5mm Gel Colors in One Pen

The Uni-ball One 3 puts black, red and blue gel ink into one compact pen. Twist the body to select a color instead of carrying three separate pens. That is especially useful if you switch colors within a page of study notes or a planner.

How does the color selection work?

Uni describes a rotating, twist-selection three-color ballpoint. Each tip in Marukaku's version is 0.5mm. Black can carry the main notes, red can mark corrections and blue can distinguish headings or dates. The number of colors is useful only if you actually switch among them.

When is a different pen better?

If you write almost exclusively in black, a single Uni-ball One may be simpler. If you need a mechanical pencil too, compare a Jetstream 4&1: its colored tips use ballpoint ink rather than the One 3's gel ink, and the body holds a separate pencil mechanism.

What to check before buying

Confirm you want the 0.5mm version and the black-red-blue arrangement. Uni sells replacement ink components for this model; match the part number before buying refills. We have not measured ink drying or smear resistance on a named notebook.

See the Uni-ball One 3 in Shirt Blue

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