Copic markers are produced by a Japanese general trading company called Too Marker Products Inc. This series called Copic Multiliner markers are suitable for works related to sketching and illustration.
The ink is made with a type of acid-free pigment ink that is durable against water and alcohol, so it does not blur or fade even if it is used with Copic markers.
This product is an assortment of four black markers diverse in tip thickness. With such a variation, you can make precise lines and draw even within a small area.