Lead of mechanical pencils
Type of core
In the market, there are 12 types of core diameters: 0.2, 0.3, 0.4, 0.5, 0.7, 0.9 mm, and the intensity is 4B to 6H (4B, 3B, 2B, B, F, HB, H, 2H, 3H, 4H, 5H, 6H). The Tombow has a core diameter of 0.3, 0.5 mm, and a Concentration of 3B to 2h.