These JOT Permanent Markers work on most surfaces. There are 8 markers, each a different color: red, orange, yellow, light green, dark green, blue violet & black (technically not a color - but all colors at once). The markers have a cone shaped point which writes 2 mm wide when first used. [the 0.4 mm wide printed information on the item label is in error]. The markers have a neutral smell [but not entirely odor free] as opposed to some markers that have a strong odor associated with them. They dry fast and are non-toxic. They conform to the American Society for Testing and Materials (ASTM) Standard D-4236.