Color band denotes SAE/Metric measurement for easy identification. Chrome vanadium steel. Fully polished for professional appearance. Mounted in convenient storage/carrying rack. Lifetime warranty. Includes 1 each: 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 17 mm, 18 mm, and 19 mm.