Uni-ball ZENTO Gel Pen 0.38 Agate

The uni-ball Zento Flow in Agate is a Japanese gel pen with a special feature in the core: The custom-developed ZENTO ink reduces writing friction by approximately 40% — writing feels noticeably smoother than with conventional gel pens. The centerpiece is the custom-developed ZENTO ink: a water-based pigment ink whose buffer components significantly reduce writing friction compared to conventional water-based inks. With a 0.38 mm conical tip, this pen is ideal for precise, detailed writing – from closely-spaced bullet journaling to intricate notes.

Features

• ZENTO Ink with Cushion Technology: Special POA surfactants act as a buffer between tip and paper and reduce writing friction by approximately 40% compared to conventional water-based inks – writing across multiple pages remains effortless.
• Pigment particles suppress feathering: The ink particles contract so that lines remain clean and sharp, even on slightly porous paper.
• Two-tone construction: ABS upper body and long aluminum grip in the same muted agate coloring – the cool, smooth feel of the metal grip gives the pen noticeably more weight than plastic versions (approximately 14 g, weight positioned near the tip).
• Spring-loaded wire clip: Opens wide enough to securely attach to notebooks, notepads or planners – in the same agate coloring as shaft and grip.
• Retractable click mechanism: The tip extends and retracts at the press of a button, no cap needed.
• Refillable: Compatible with ZENTO refills in 0.38 mm and 0.5 mm as well as black, blue and red – when refilling, you can also change the line width.
• Black pigment ink, not archival: Quick-drying, smudge- and water-resistant; the water-based formulation is suitable for general writing but is not certified for archival or document requirements.

Application & Tips

• Bullet journaling and tight grids: The 0.38 mm tip produces a fine line that remains clearly legible in 3.5 mm grids and tight layouts without fading.
• Ink-resistant, calendered paper: On smooth, closed paper, the ZENTO ink shows its full potential – minimal feathering, quick drying, barely any show-through.
• Left-handers: The quick drying of the pigment-based ink significantly reduces the risk of smudging when writing over fresh lines.
• Grip position: The aluminum grip is cool and smooth; if you prefer a firmer grip, write with slightly more finger pressure or use a finger ring grip as an aid. The weight is positioned close to the tip, which sets the center of gravity pleasantly low.
• Change refill: The refill can be removed by gently pulling it forward. When refilling, you can also switch to 0.5 mm – same pen body, different line width.
• Archival notes: For documents with long-term requirements (contracts, official documents), choose an archival-quality alternative; for journaling, planning and everyday notes, the ZENTO ink is well-suited.

For Stationery Enthusiasts

The ZENTO ink is described by Mitsubishi Uni as a water-based pigment ink with an innovative buffer component – a POA surfactant that works between ball and paper and reduces friction by approximately 40% compared to previous Uni water-based inks. At the same time, the pigment particles ensure that the ink contracts on the paper surface rather than feathering. The result is a line that appears denser and sharper than many other 0.38 mm gel inks. Interesting for pen enthusiasts: The refill is compatible with the Schmidt/Euro refill format, so it can also be used in other pens with this standard – and conversely, compatible refills fit in the ZENTO body.

Technical Specifications