Permanent marker (round core) that produces vivid color even when writing on metal, glass, or black paper. Opaque ink writes vividly on black objects Ink Color: White; Medium Point; Line Width: 0.09 - 0.1 inches (2.2 - 2.8 mm); Ink: Opaque, Oil-based; Material: Shaft: Aluminum; Pen Core: Sliver (Acrylic); Product Size: Diameter 0.6 inches (15.1 mm) x Total Length: 5.6 inches (141.8 mm); Weight: 0 oz (21.8 g).