Zig markers are double-ended, with two chisel nibs for calligraphy and lettering. The large nib is 5.0mm and the small nib is 2.0mm. The ink has archival quality lightfastness and is photo safe. It is water-based and will not bleed. This set includes all the Pure colors: Black, Red, Pink, Yellow, Green, Blue, Violet, and Brown. Store horizontally to prevent dryness in one end. We are having a difficulty stocking this item.