These Pilot SCA-B Super Color Permanent Markers are made from a sturdy, aluminum barrel and have a large ink tank. The chisel shaped tip writes sharp letters and bold strokes on most indoor and outdoor surfaces. The ink inside this marker is xylene free. These markers have a 2.0 mm nib on the tip and a broad 4.5 mm line on the side. The chisel nib allows you to draw both fine and broad lines. The large ink tank ensures the markers last a long time. The pens have a strong, aluminum barrel. This pen writes on most indoor and outdoor surfaces.