What you are viewing are Colourful Fluorescent Markers 4 Pack. These fluorescent markers are perfect for writing on windows, marker boards and black boards. Bright colors take on a neon look under ultraviolet light. Messages can be changed frequently with these fluorescent pens, as they are easy to clean by using a damp or wet cloth. Use Highlighter Pen on chalkboards, dry-erase boards, light boards, windows and windshields. Opaque, water-based, pigmented formula is erasable with a damp cloth. Colourful Fluorescent Markers for use on black marker boards, fluorescent light boards or glass. Pen-style cheap fluorescent markers let you write clearly, without ink bleed-out that can blur lines.