Thanks to the new technology and the combination of materials the particles firmly adhere to the surface of the paper, so the line does not smear. You can freely mark the text with a text marker over the writing line. Black graphite reinforced with oils with a lubricating effect gives smoothness to the graphite, enabling stronger pressure on the paper and giving you a soft feeling when writing. It reduces the kinetic friction between the paper and the lead and enables vivid, clear lines. One tube contains 12 leads. Lead diameter: 0.5 mm. The price is for one tube, commercial packaging is 12 tubes.