The WorkPro 8-Piece Folding Hex Key Set is constructed of CR-V steel for strength and long-lasting performance. The finish provides resistance to corrosion. The keys fold up within the handle for efficient organization.It is designed to tighten and loosen hex fasteners. All folding key sets feature a comfortable grip for non-slip usage. The keys are made with hardened steel and feature a flat-end, industrial-quality design. Set includes 1.5, 2, 2.5, 3, 4, 5, 6, 8 mm With this kind of range of sizes you will have a hard time finding a job you can't tackle.This folding hex key set is perfect for DIY home maintenance, garden projects, and much more!