If you want to draw and sketch with precision, you need Geo-liner. Ideal for drawing with templates. The color code indicates the thickness of the line. The ink is water and light resistant. Display unit WxHxD: 16,0x18,0x21,5 cm. Contents: 7x23501 (0.1mm), 6x23503 (0.3mm), 12x23505 (0.5mm) and 5x23507 (0.7mm)