The NN50 permanent marker from Pentel is an environmentally friendly and waterproof felt-tip pen. The black pen has a round acrylic fiber tip. The formula is alcohol-based and contains no xylene or toluene. The ink is smudge-proof and waterproof, so that markings remain visible for longer. With a line width of 1.3mm to 3mm, the marker is suitable for both fine and broader markings.