The photoluminescent oil color of the Glow-in-the-Dark Sakura Solid Marker gets charged by the light and glows in the dark, so that markings are visible in the dark. The Sakura Solid Markers can be used on virtually all surfaces such as wood, fabric, plastic, metal, rubber, cardboard and concrete, even oily, rusty, dusty and wet surfaces are no obstacle. The line width is approx. 13mm.