A special drawing black lead measuring 5.6 mm in diameter. Its is produced in three hardness degrees: 1, 2, 3. It is distinguished by a strong black velvet mark. It is widely used for portraying as well as for other types of drawing. Artists seem to like it. 5.6mm Lead Refills for Drawing. accessible in three distinct grade levels. The length of the clutch pencils is 120mm. produced in the Czech Republic.