You can mark permanently most anything with real paint pens. These pens are great for marking laboratory equipment and much more. The opaque, weatherproof enamel dries to a glossy finish in seconds. The paint pen with its pressure sensitive felt tip applies smoothly on glass, leather, stone, wood, metal, vinyl, paper, plastic, etc. Shake the pen for 60 seconds to insure proper mix of paint and you will be able to writeout 150 meters. Paint pens are available in either a fine point, approx. 2.5 mm wide, or a medium point, approx. 4 mm wide.