Each one of Kimball Midwest's Metric Blue Hex Key Sets comes with a tough carrying case that IDs the size of each hex key. The 9-piece sets range from M1.5 to M10 and the 12-piece sets range from M1.5 to M17. The dual-purpose Metric Blue "Extreme" coating not only removes confusion by adding instant tool ID, it also provides 1000-hour salt spray protection, which is up to 25 times the corrosion protection of conventional hex key tools.