This cartridge is specifically designed for the Shunpitsu brush pen.

The ink dries quickly, so your hands and the writing won't get dirty.

It's also recommended for those who have struggled with brush pens because the ink dries slowly and smudges the writing.

Water-based dye / quick-drying ink: 6.5g

Refill for Fine Black Brush Pen SVS-70FDF-B or Medium Black Brush Pen SVS-70FDM-B