Description. This opaque ink allows you to write clearly on black objects. Double-headed design allows for use of two different thicknesses in a single ink. Recommended for wood, glass, plastic, and metal. Not suitable for soft vinyl chloride products such as floats. The shaft and cap are made of resin. Mackie Paint Marker】Can be used to write clearly on black objects! Opaque ink [Features] Suitable for wood, glass, metal, and plastic! Features] Suitable for wood, glass, metal, and plastic.