These pens provide maximum lightfastness are water-resistant and contain permanent pigmented drawing ink. They are odor-free, acid-free and pH neutral. The pens provide a variety of 4 line widths: B = brush nib, 1.5 = 1.5 mm bullet nib, C = Calligraphy nib in white, S = 0.3 mm in black. These pens are ideal for sketches, drawings, layouts, fashion design and illustrations. Good for setting highlights and for use on dark papers.