The IDenti-Pen has dual points, one medium and one fine, for line versatility it is built for heavy use. The low-odor, non-toxic ink is permanent and waterproof on almost all non-porous surfaces. IDENTI-PEN® black is a multi-purpose pen that marks on almost any surface. The dual point IDenti-pen is two, permanent sharp-pointed marking pens in one: a tough fiber nib tip, fine-point bullet nib on one end and an extra fine plastic tip for details on the other. Use this pen on paper products and non-porous surfaces such as metal, glass, tools, sporting goods, test tubes, photographs, plastics, vinyl, wood products, and labels.