These bullet nib can produce a line of 1.5mm. They offer odorless, permanent and waterproof inks in vibrant colors that will not bleed through paper. The pigmented India inks are perfectly opaque lightfast, acid-free and pH Neutral. The pens are used daily by artists worldwide for illustrations, fashion design, life drawings, portraits, sequential art and canvas paintings. They work beautifully on all types of papers and canvas, permanent on porous surfaces. Store horizontally when not in use.