This is a brush pen that is fitted with an ultra-fine brush tip similar to those found in eyeliner cosmetics.\”ai Liner\” was made possible due to the experience gained from manufacturing not only inks, pens and brushes, but also cosmetics, which Kuretake has a hand in as well. The ultra fine brush \”ai Liner\” is elastic and has excellent maneuverability and control, and so it is perfect for delicate expressions in illustration as well as hand lettering.