Every facet of fine line detailing and permanence is incorporated into this pen to execute writing in microspaces or on unusual and challenging surfaces. Microperm is used to make precise longlasting marks on test tubes, circuit boards, diamonds, cellophane, wood and glass, plastic, metal, or wherever there is a need for waterproof ink that will write on nonporous surfaces. Diamond cutters can use microperm to make minute markings on rough diamonds to insure exact cuts. Permanent adherence to most surfaces. A fine line nib with a protected tip that will not split. Writes on crafts, test tubes, beakers, engineering templates, rulers diamonds, glass, wood, cellophane, plastic and glossy sheets, cds, photographic and xray film, paper and metal. Comes with three point sizes. Protected tips will not split. Permanent on most surfaces, waterproof, low odor, meets acmi nontoxicity standards, not recommended for use on fabrics intended to be washed and not evaluated for cosmetic use on skin. Available in black color. Set consists 1 each of 01, 03 and 05 pen.