Ai Liner Ultra Fine Tip Brush Pen / Kuretake

• Tip: Ultra-fine brush (polyester)
• Ink Type: Water-based pigment ink
• Water Resistance: Water-resistant when dry
• Body Diameter: 9.5mm
• Length: 120mm
• Weight: 5.3g
• Body Material: Polypropylene (PP)
• Ink System: Direct-fill (no cartridge)
• Available Colors: Black, Brown, Sepia, Gray

Kuretake has spent decades developing high-quality pen bodies and brush tips for the cosmetics industry. The Ai Liner (愛ライナー) draws directly on that background: the ultra-fine brush tip is the same type used in cosmetic eyeliners, engineered to a precision that most calligraphy or illustration brush pens do not reach.

The name references the eyeliner it takes its cues from, and the body matches that inspiration, slim and compact at 9.5mm in diameter. The tip has a firm spring that gives it fine control down to very small detail work. Kuretake points out it is fine enough to write characters on a grain of rice.

The direct-fill ink system means there is no cartridge to swap and the ink runs to the very end without waste. Because the pigment is water-resistant once dry, the pen works well as a liner in mixed-media illustration, holding its line under both water-based and alcohol markers applied on top.