Koh-I-Noor Gioconda Artists' artificial drawing charcoal - Medium form which is the ultimate alternative to natural charcoals. Artificial charcoal burnt into lead shape; it is mainly intended for use with mechanical pencils. These leads blend easily and are extremely easy to use. They allow you to produce a smooth, beautiful texture. Each lead has a round profile of 5.6 mm diameter and measures 75 mm in length.