This gell-ink ballpoint pen writes very well! Aranzi Signo Pen (black) has comes with a 0.28mm rollerball, which can provide thinner strokes than the regular Aranzi Signo Pens.
Uni-ball Signo by MITSUBISHIPENCIL CO., LTD. Ultra fine 0.28mm Ink color: black / waterproof gell-ink