Uni NanoDia Low-Wear Pencil Leads 0.3 mm B, 15 Leads X 5 Pack/total 75 Leads (Japan Import) [Komainu-Dou Original Package] Lead diameter: 0.3mm Hardness: B It is a mechanical pencil lead which combined Nanodaiya of 400 million units in the lead of one of them. It provides a considerable strength. It is possible to draw smoothly.