-High grade S2 Alloy Steel used. -Hardness of 58-60HRC, done as per international standards, for high torsional strength and high deformation resistance, for long life. Never Before: -Extra shine-mirror finish, along with protective coating, for good aesthetics and prevention from rust. -Unique jacket to hold all the hex keys in their respective places for convenience. Note: Please also ask for our ball type Allen keys in Long and extra long series, having all the features as above, along with the unique application of ball end.