Highly opaque carbon ink by the japanese manufacturer Platinum. The ink is pigmented and is waterproof after drying. It is suitable for both brush pens and fountain pens.
Pigmented inks are intended for use in fountain pens, but require careful maintenance and shouldn't dry out in the fountain pen. It is best to clean the pen at least once a week to avoid clogging. Certain pens can handle pigmented inks better than others.