Identi-pen is a dual-point multi-purpose marker that will mark most non-porous surfaces. It's easy to label personal items with your contact information, or decorate with illustrations and patterns. Use Identi-pen to mark on a wide variety of difficult surfaces, such as wood, metal, plastic, glass, golf balls, CDs, and slick paper. Identi-pen is often used for autographs from your favorite musician, athlete, or actor on photos and memorabilia.