Every artist can appreciate these double-ended art markers. The ink is formulated to give the richest color saturation with silky smooooooth coverage. Includes 12 Markers: Black (x3)•Cool Gray 10% ,Cool Gray 20% ,Cool Gray 30% ,Cool Gray 40% ,Cool Gray 50% ,Cool Gray 60% ,Cool Gray 70% ,Cool Gray 80% ,Cool Gray 90%