Strength & Deep & Smooth -Uni-ball Extra Fine Diamond Infused Pencil Leads, 0.5 mm-2B-Nano Dia 40 Leads x 3 Pack/Total 120 Leads/ Uni develops the lead of the top quality Intensity of the lead was sharply strengthened by blending the particles of a diamond. Since particles have aligned by high density, it can write distinctly still more deeply And it can draw more smoothly. My Store is The goods of High quality and popular Japan are selected carefully and it sells with reasonable set pricing. Since many inexpensive sets are sold, please search by "Value set".