Caran d'Ache Artists Professional 100 Luminance 6901 Coloured Pencils Set is the colour pencil that combines the best possible lightfastness with the smoothness of a permanent lead made with wax. In accordance with the international ASTM D-6901 standard (which certifies the lightfastness of colours on a scale from LFI to LFV), Luminance 6901® offers to the demands of the most exacting creative professionals the guarantee that their works will stand the test of time for up to 100 years.